1. Procedure may or may not return value where as function should return one value.

2. Function can be called from SQL statement where as procedure can’t be called from the SQL statement.

3. Function are normally used for computation where as procedure are normally used for executing business logic.

4. Stored procedure is pre-compiled execution plan where as function are not.

5. We can call function within procedure but we can not call procedure within function.

6. A FUNCTION must be part of an executable statement, as it cannot be executed independently, whereas procedure represents an independent executable statement.

and for example of both syntax of function and procedure :

[code]CREATE OR REPLACE PROCEDURE test_proc
(p_id IN VARCHAR2) as begin … end

CREATE OR REPLACE FUNCTION test_func
(p_id IN VARCHAR2) return varchar2 as begin … end[/code]

hope this help.