diff --git a/packages/nodes-base/credentials/MailchimpOAuth2Api.credentials.ts b/packages/nodes-base/credentials/MailchimpOAuth2Api.credentials.ts
new file mode 100644
index 0000000000..0a0efc7091
--- /dev/null
+++ b/packages/nodes-base/credentials/MailchimpOAuth2Api.credentials.ts
@@ -0,0 +1,68 @@
+import {
+	ICredentialType,
+	NodePropertyTypes,
+} from 'n8n-workflow';
+
+
+export class MailchimpOAuth2Api implements ICredentialType {
+	name = 'mailchimpOAuth2Api';
+	extends = [
+		'oAuth2Api',
+	];
+	displayName = 'Mailchimp OAuth2 API';
+	properties = [
+		{
+			displayName: 'Mailchimp Server',
+			name: 'server',
+			type: 'string' as NodePropertyTypes,
+			default: 'https://login.mailchimp.com/',
+			description: 'The server to connect to.',
+		},
+		{
+			displayName: 'Datacenter',
+			name: 'dataCenter',
+			type: 'string' as NodePropertyTypes,
+			default: 'us10',
+			description: 'Datacenter that your Mailchimp application is hosted on. Found in the URL of your Mailchimp dashboard.',
+		},
+		{
+			displayName: 'Authorization URL',
+			name: 'authUrl',
+			type: 'hidden' as NodePropertyTypes,
+			default: 'https://login.mailchimp.com/oauth2/authorize',
+			required: true,
+		},
+		{
+			displayName: 'Access Token URL',
+			name: 'accessTokenUrl',
+			type: 'hidden' as NodePropertyTypes,
+			default: 'https://login.mailchimp.com/oauth2/token',
+			required: true,
+		},
+		{
+			displayName: 'Metadata',
+			name: 'metadataUrl',
+			type: 'hidden' as NodePropertyTypes,
+			default: 'https://login.mailchimp.com/oauth2/metadata',
+			required: true,
+		},
+		{
+			displayName: 'Scope',
+			name: 'scope',
+			type: 'hidden' as NodePropertyTypes,
+			default: '',
+		},
+		{
+			displayName: 'Auth URI Query Parameters',
+			name: 'authQueryParameters',
+			type: 'hidden' as NodePropertyTypes,
+			default: '',
+		},
+		{
+			displayName: 'Authentication',
+			name: 'authentication',
+			type: 'hidden' as NodePropertyTypes,
+			default: 'header',
+		},
+	];
+}
diff --git a/packages/nodes-base/nodes/Mailchimp/GenericFunctions.ts b/packages/nodes-base/nodes/Mailchimp/GenericFunctions.ts
index 91dfcdde85..3d66c2d8ab 100644
--- a/packages/nodes-base/nodes/Mailchimp/GenericFunctions.ts
+++ b/packages/nodes-base/nodes/Mailchimp/GenericFunctions.ts
@@ -1,5 +1,5 @@
 import {
-	OptionsWithUri,
+	OptionsWithUrl,
  } from 'request';
 
 import {
@@ -14,35 +14,51 @@ import {
  } from 'n8n-workflow';
 
 export async function mailchimpApiRequest(this: IHookFunctions | IExecuteFunctions | IExecuteSingleFunctions | ILoadOptionsFunctions, endpoint: string, method: string, body: any = {}, qs: IDataObject = {} ,headers?: object): Promise<any> { // tslint:disable-line:no-any
-	const credentials = this.getCredentials('mailchimpApi');
-
-	if (credentials === undefined) {
-		throw new Error('No credentials got returned!');
-	}
-
-	const headerWithAuthentication = Object.assign({}, headers, { Authorization: `apikey ${credentials.apiKey}` });
-
-	if (!(credentials.apiKey as string).includes('-')) {
-		throw new Error('The API key is not valid!');
-	}
-
-	const datacenter = (credentials.apiKey as string).split('-').pop();
+	const authenticationMethod = this.getNodeParameter('authentication', 0) as string;
 
 	const host = 'api.mailchimp.com/3.0';
 
-	const options: OptionsWithUri = {
-		headers: headerWithAuthentication,
+	const options: OptionsWithUrl = {
+		headers: {
+			'Accept': 'application/json'
+		},
 		method,
 		qs,
-		uri: `https://${datacenter}.${host}${endpoint}`,
+		body,
+		url: ``,
 		json: true,
 	};
 
-	if (Object.keys(body).length !== 0) {
-		options.body = body;
+	if (Object.keys(body).length === 0) {
+		delete options.body;
 	}
+
 	try {
-		return await this.helpers.request!(options);
+		if (authenticationMethod === 'accessToken') {
+			const credentials = this.getCredentials('mailchimpApi');
+	
+			if (credentials === undefined) {
+				throw new Error('No credentials got returned!');
+			}
+	
+			options.headers = Object.assign({}, headers, { Authorization: `apikey ${credentials.apiKey}` });
+	
+			if (!(credentials.apiKey as string).includes('-')) {
+				throw new Error('The API key is not valid!');
+			}
+	
+			const datacenter = (credentials.apiKey as string).split('-').pop();
+			options.url = `https://${datacenter}.${host}${endpoint}`;
+			
+			return await this.helpers.request!(options);
+		} else {
+			const credentials = this.getCredentials('mailchimpOAuth2Api');
+			const datacenter = credentials!.dataCenter;
+	
+			options.url = `https://${datacenter}.${host}${endpoint}`;
+			//@ts-ignore
+			return await this.helpers.requestOAuth2!.call(this, 'mailchimpOAuth2Api', options, 'bearer');
+		}
 	} catch (error) {
 		if (error.response.body && error.response.body.detail) {
 			throw new Error(`Mailchimp Error response [${error.statusCode}]: ${error.response.body.detail}`);
diff --git a/packages/nodes-base/nodes/Mailchimp/Mailchimp.node.ts b/packages/nodes-base/nodes/Mailchimp/Mailchimp.node.ts
index cb54ac24e9..3b8d17c302 100644
--- a/packages/nodes-base/nodes/Mailchimp/Mailchimp.node.ts
+++ b/packages/nodes-base/nodes/Mailchimp/Mailchimp.node.ts
@@ -69,9 +69,44 @@ export class Mailchimp implements INodeType {
 			{
 				name: 'mailchimpApi',
 				required: true,
-			}
+				displayOptions: {
+					show: {
+						authentication: [
+							'accessToken',
+						],
+					},
+				},
+			},
+			{
+				name: 'mailchimpOAuth2Api',
+				required: true,
+				displayOptions: {
+					show: {
+						authentication: [
+							'oAuth2',
+						],
+					},
+				},
+			},
 		],
 		properties: [
+			{
+				displayName: 'Authentication',
+				name: 'authentication',
+				type: 'options',
+				options: [
+					{
+						name: 'Access Token',
+						value: 'accessToken',
+					},
+					{
+						name: 'OAuth2',
+						value: 'oAuth2',
+					},
+				],
+				default: 'accessToken',
+				description: 'Method of authentication.',
+			},
 			{
 				displayName: 'Resource',
 				name: 'resource',
@@ -1536,6 +1571,7 @@ export class Mailchimp implements INodeType {
 					responseData = { success: true };
 				}
 			}
+			
 			if (Array.isArray(responseData)) {
 				returnData.push.apply(returnData, responseData as IDataObject[]);
 			} else {
diff --git a/packages/nodes-base/nodes/Mailchimp/MailchimpTrigger.node.ts b/packages/nodes-base/nodes/Mailchimp/MailchimpTrigger.node.ts
index 25eac04c20..67e07ad6bd 100644
--- a/packages/nodes-base/nodes/Mailchimp/MailchimpTrigger.node.ts
+++ b/packages/nodes-base/nodes/Mailchimp/MailchimpTrigger.node.ts
@@ -33,7 +33,25 @@ export class MailchimpTrigger implements INodeType {
 			{
 				name: 'mailchimpApi',
 				required: true,
-			}
+				displayOptions: {
+					show: {
+						authentication: [
+							'accessToken',
+						],
+					},
+				},
+			},
+			{
+				name: 'mailchimpOAuth2Api',
+				required: true,
+				displayOptions: {
+					show: {
+						authentication: [
+							'oAuth2',
+						],
+					},
+				},
+			},
 		],
 		webhooks: [
 			{
@@ -50,6 +68,23 @@ export class MailchimpTrigger implements INodeType {
 			}
 		],
 		properties: [
+			{
+				displayName: 'Authentication',
+				name: 'authentication',
+				type: 'options',
+				options: [
+					{
+						name: 'Access Token',
+						value: 'accessToken',
+					},
+					{
+						name: 'OAuth2',
+						value: 'oAuth2',
+					},
+				],
+				default: 'accessToken',
+				description: 'Method of authentication.',
+			},
 			{
 				displayName: 'List',
 				name: 'list',
diff --git a/packages/nodes-base/package.json b/packages/nodes-base/package.json
index 31cb4a8da5..f1ce8536a6 100644
--- a/packages/nodes-base/package.json
+++ b/packages/nodes-base/package.json
@@ -78,6 +78,7 @@
             "dist/credentials/KeapOAuth2Api.credentials.js",
             "dist/credentials/LinkFishApi.credentials.js",
             "dist/credentials/MailchimpApi.credentials.js",
+            "dist/credentials/MailchimpOAuth2Api.credentials.js",
             "dist/credentials/MailgunApi.credentials.js",
             "dist/credentials/MailjetEmailApi.credentials.js",
             "dist/credentials/MailjetSmsApi.credentials.js",