diff --git a/docs/UserGuide.adoc b/docs/UserGuide.adoc
index 4abb17e3e..96cf40d1b 100644
--- a/docs/UserGuide.adoc
+++ b/docs/UserGuide.adoc
@@ -151,6 +151,11 @@ Views all details of the 2nd person in the address book.
 `viewall 1` +
 Views all details of the 1st person in the results of the `find` command.
 
+== Show the number of person in the address book : `size`
+
+Format: `size`
+
+
 == Clearing all entries : `clear`
 
 Clears all entries from the address book. +
diff --git a/src/seedu/addressbook/commands/HelpCommand.java b/src/seedu/addressbook/commands/HelpCommand.java
index 9be217d89..521b4f6a2 100644
--- a/src/seedu/addressbook/commands/HelpCommand.java
+++ b/src/seedu/addressbook/commands/HelpCommand.java
@@ -1,6 +1,8 @@
 package seedu.addressbook.commands;
 
 
+import javafx.css.Size;
+
 /**
  * Shows help instructions.
  */
@@ -21,6 +23,7 @@ public CommandResult execute() {
                 + "\n" + ListCommand.MESSAGE_USAGE
                 + "\n" + ViewCommand.MESSAGE_USAGE
                 + "\n" + ViewAllCommand.MESSAGE_USAGE
+                + "\n" + SizeCommand.MESSAGE_USAGE
                 + "\n" + HelpCommand.MESSAGE_USAGE
                 + "\n" + ExitCommand.MESSAGE_USAGE
         );
diff --git a/src/seedu/addressbook/commands/SizeCommand.java b/src/seedu/addressbook/commands/SizeCommand.java
new file mode 100644
index 000000000..faf18ba75
--- /dev/null
+++ b/src/seedu/addressbook/commands/SizeCommand.java
@@ -0,0 +1,21 @@
+package seedu.addressbook.commands;
+
+/**
+ * Shows help instructions.
+ */
+public class SizeCommand extends Command {
+
+    public static final String COMMAND_WORD = "size";
+
+    public static final String MESSAGE_USAGE = COMMAND_WORD + ": Show the size of the address book.\n"
+            + "Example: " + COMMAND_WORD;
+
+    @Override
+    public CommandResult execute() {
+        if (addressBook.size() == 0)
+            return new CommandResult("There is no person in the address book.");
+        else if (addressBook.size() == 1)
+            return new CommandResult("There is one person in the address book.");
+        else return new CommandResult("There are " + addressBook.size() + " persons in the address book.");
+    }
+}
\ No newline at end of file
diff --git a/src/seedu/addressbook/data/AddressBook.java b/src/seedu/addressbook/data/AddressBook.java
index 537d35c89..9ea020ee1 100644
--- a/src/seedu/addressbook/data/AddressBook.java
+++ b/src/seedu/addressbook/data/AddressBook.java
@@ -68,6 +68,11 @@ public UniquePersonList getAllPersons() {
         return new UniquePersonList(allPersons);
     }
 
+    /**
+     * Show the size of the address book
+     */
+    public int size() {return allPersons.size();}
+
     @Override
     public boolean equals(Object other) {
         return other == this // short circuit if same object
diff --git a/src/seedu/addressbook/data/person/UniquePersonList.java b/src/seedu/addressbook/data/person/UniquePersonList.java
index d7acd8b4a..57a0b3bef 100644
--- a/src/seedu/addressbook/data/person/UniquePersonList.java
+++ b/src/seedu/addressbook/data/person/UniquePersonList.java
@@ -122,6 +122,11 @@ public void remove(ReadOnlyPerson toRemove) throws PersonNotFoundException {
         }
     }
 
+    /**
+     * Return the size of the list
+     */
+    public int size() {return internalList.size();};
+
     /**
      * Clears all persons in list.
      */
diff --git a/src/seedu/addressbook/parser/Parser.java b/src/seedu/addressbook/parser/Parser.java
index abddb3f45..fc6f0d355 100644
--- a/src/seedu/addressbook/parser/Parser.java
+++ b/src/seedu/addressbook/parser/Parser.java
@@ -22,6 +22,7 @@
 import seedu.addressbook.commands.ListCommand;
 import seedu.addressbook.commands.ViewAllCommand;
 import seedu.addressbook.commands.ViewCommand;
+import seedu.addressbook.commands.SizeCommand;
 import seedu.addressbook.data.exception.IllegalValueException;
 
 /**
@@ -97,6 +98,9 @@ public Command parseCommand(String userInput) {
         case ExitCommand.COMMAND_WORD:
             return new ExitCommand();
 
+        case SizeCommand.COMMAND_WORD:
+            return new SizeCommand();
+
         case HelpCommand.COMMAND_WORD: // Fallthrough
         default:
             return new HelpCommand();