diff --git a/bin/console b/bin/console
new file mode 100755
index 0000000..99dc6e3
--- /dev/null
+++ b/bin/console
@@ -0,0 +1,14 @@
+#!/usr/bin/env ruby
+
+require "bundler/setup"
+require "amplitude-api"
+
+# You can add fixtures and/or initialization code here to make experimenting
+# with your gem easier. You can also use a different console, if you like.
+
+# (If you use this, don't forget to add pry to your Gemfile!)
+# require "pry"
+# Pry.start
+
+require "irb"
+IRB.start(__FILE__)
diff --git a/lib/amplitude_api.rb b/lib/amplitude_api.rb
index 8fc285f..8999bc1 100644
--- a/lib/amplitude_api.rb
+++ b/lib/amplitude_api.rb
@@ -13,6 +13,8 @@ class AmplitudeAPI
   IDENTIFY_URI_STRING     = "https://api2.amplitude.com/identify"
   SEGMENTATION_URI_STRING = "https://amplitude.com/api/2/events/segmentation"
   DELETION_URI_STRING     = "https://amplitude.com/api/2/deletions/users"
+  COHORTS_URI_STRING      = "https://amplitude.com/api/3/cohorts"
+  MEMBERSHIP_URI_STRING   = "https://amplitude.com/api/3/cohorts/membership"
 
   USER_WITH_NO_ACCOUNT = "user who doesn't have an account"
 
@@ -169,6 +171,8 @@ def segmentation(event, start_time, end_time, **options)
       }.delete_if { |_, value| value.nil? }
     end
 
+    # ==== User Deletion related methods
+
     # Delete a user from amplitude
     #
     # You must pass in either an array of user_ids or an array of amplitude_ids
@@ -188,9 +192,7 @@ def delete(user_ids: nil, amplitude_ids: nil, requester: nil, ignore_invalid_id:
       user_ids = Array(user_ids)
       amplitude_ids = Array(amplitude_ids)
 
-      faraday = Faraday.new do |conn|
-        conn.request :basic_auth, config.api_key, config.secret_key
-      end
+      faraday = connection_with_basic_auth
 
       faraday.post(
         DELETION_URI_STRING,
@@ -199,6 +201,56 @@ def delete(user_ids: nil, amplitude_ids: nil, requester: nil, ignore_invalid_id:
       )
     end
 
+    # ==== Behavioural Cohort related methods
+
+    # Get all cohorts
+    #
+    # See https://www.docs.developers.amplitude.com/analytics/apis/behavioral-cohorts-api/#get-all-cohorts
+    #
+    # @return [ Faraday::Response ]
+    def get_cohorts
+      faraday = connection_with_basic_auth
+
+      faraday.get(COHORTS_URI_STRING, nil, "Content-Type" => "application/json")
+    end
+
+    # Add one or more users to a cohort
+    #
+    # See https://www.docs.developers.amplitude.com/analytics/apis/behavioral-cohorts-api/#update-cohort-membership
+    #
+    # @param [ String ] the ID of the cohort to add the users to
+    # @param [ Array<String> ] the user_ids (NOT amplitude_ids) that should be
+    # added to this cohort
+    # @return [ Faraday::Response ]
+    def add_to_cohort(cohort_id:, user_ids:)
+      update_cohort(cohort_id: cohort_id, user_ids: user_ids, operation: 'ADD')
+    end
+
+    # Remove one or more users from a cohort
+    #
+    # See https://www.docs.developers.amplitude.com/analytics/apis/behavioral-cohorts-api/#update-cohort-membership
+    #
+    # @param [ String ] the ID of the cohort to add the users to
+    # @param [ Array<String> ] the user_ids (NOT amplitude_ids) that should be
+    # removed from this cohort
+    # @return [ Faraday::Response ]
+    def remove_from_cohort(cohort_id:, user_ids:)
+      update_cohort(cohort_id: cohort_id, user_ids: user_ids, operation: 'REMOVE')
+    end
+
+    # Convenience helper method to add/remove users from a cohort
+    #
+    # See https://www.docs.developers.amplitude.com/analytics/apis/behavioral-cohorts-api/#update-cohort-membership
+    def update_cohort(cohort_id:, user_ids:, operation:)
+      faraday = connection_with_basic_auth
+
+      faraday.post(
+        MEMBERSHIP_URI_STRING,
+        update_cohort_body(cohort_id: cohort_id, user_ids: user_ids, operation: operation),
+        "Content-Type" => "application/json"
+      )
+    end
+
     private
 
     def delete_body(user_ids, amplitude_ids, requester, ignore_invalid_id, delete_from_org)
@@ -212,5 +264,25 @@ def delete_body(user_ids, amplitude_ids, requester, ignore_invalid_id, delete_fr
       body[:delete_from_org] = delete_from_org.to_s if delete_from_org
       JSON.generate(body)
     end
+
+    def update_cohort_body(cohort_id:, user_ids:, operation:)
+      {
+       cohort_id: cohort_id,
+       memberships: [
+         {
+            ids: user_ids,
+            id_type: 'BY_NAME',
+            operation: operation
+          }
+        ],
+       skip_invalid_ids: true
+     }.to_json
+    end
+
+    def connection_with_basic_auth
+      Faraday.new do |conn|
+        conn.request :basic_auth, config.api_key, config.secret_key
+      end
+    end
   end
 end
diff --git a/readme.md b/readme.md
index 62c4125..491942a 100644
--- a/readme.md
+++ b/readme.md
@@ -78,6 +78,37 @@ AmplitudeAPI.delete(user_ids: ["12345"],
 )
 ```
 
+
+## Behavioural Cohorts APIs
+
+See the [Amplitude docs on Behavioural Cohorts](https://www.docs.developers.amplitude.com/analytics/apis/behavioral-cohorts-api).
+
+```ruby
+# Configure your Amplitude API key & secret key
+AmplitudeAPI.config.api_key = "abcdef123456"
+AmplitudeAPI.config.secret_key = "secretMcSecret"
+
+# Get all cohorts
+response = AmplitudeAPI.get_cohorts
+
+if response.status == 200
+  data = JSON.parse(response.body)
+
+  # print the ID & name of each cohort
+  data['cohorts'].each { |c| puts "id=#{c['id']} name=#{c['name']}" }
+end
+
+# Add / remove users from a cohort
+# You need to use the same user_ids you use when identifying users with the identify API
+
+# Incrementally add users to a cohort
+AmplitudeAPI.add_to_cohort(cohort_id: 'abcd123', user_ids: ['1234', '5678'])
+
+# Incrementally remove users from a cohort
+AmplitudeAPI.add_to_cohort(cohort_id: 'abcd123', user_ids: ['1234', '5678'])
+```
+
+
 Currently, we are using this in Rails and using ActiveJob to dispatch events asynchronously. I plan on moving
 background/asynchronous support into this gem.