diff --git a/lib/t/cli.rb b/lib/t/cli.rb
index 5ae10471..4cc5cd49 100644
--- a/lib/t/cli.rb
+++ b/lib/t/cli.rb
@@ -112,6 +112,8 @@ def authorize
     desc 'block USER [USER...]', 'Block users.'
     method_option 'id', aliases: '-i', type: :boolean, desc: 'Specify input as Twitter user IDs instead of screen names.'
     def block(user, *users)
+      return if invalid_users_present(user, users)
+
       blocked_users, number = fetch_users(users.unshift(user), options) do |users_to_block|
         client.block(users_to_block)
       end
@@ -950,6 +952,38 @@ def whoami
 
   private
 
+    def invalid_users_present(user, users)
+      not_found_flag = false
+      begin
+        if user_already_blocked?(user)
+          say "#{user} is already blocked\n"
+        end
+        rescue
+          say "#{user} not found \n"
+          return true if users.empty?
+        ensure
+          users.each do |user|
+            begin
+              return true if user_already_blocked?(user)
+            rescue
+              say "#{user} not found \n"
+              not_found_flag = true
+              next
+            end
+          end
+          not_found_flag
+      end
+      not_found_flag
+    end
+
+    def user_already_blocked?(user)
+      if client.block?(user)
+        say "#{user} is already blocked"
+        return true
+      end
+      return false
+    end
+
     def extract_mentioned_screen_names(text)
       valid_mention_preceding_chars = /(?:[^a-zA-Z0-9_!#\$%&*@＠]|^|RT:?)/o
       at_signs = /[@＠]/
diff --git a/spec/cli_spec.rb b/spec/cli_spec.rb
index 5646f6cc..7a872e71 100644
--- a/spec/cli_spec.rb
+++ b/spec/cli_spec.rb
@@ -111,6 +111,12 @@
       @cli.block('sferik')
       expect(a_post('/1.1/blocks/create.json').with(body: {screen_name: 'sferik'})).to have_been_made
     end
+
+    it 'notifies of invalid user' do
+      @cli.block('vinuthalan')
+      expect($stdout.string).to match('@testcli blocked 1 user')
+    end
+    
     it 'has the correct output' do
       @cli.block('sferik')
       expect($stdout.string).to match(/^@testcli blocked 1 user/)