A circular patch antenna with a narrow slit is proposed to achieve multi frequency, dual band operation. The proposed antenna radiates at four different frequencies with sufficiently high matching with probe feed system. Among these four frequencies two frequencies 2.62 GHz and 5.82 GHz lies in lower and upper frequency band respectively of Wi-Max application created by IEEE 802.16 working group. It is also observed that its radiation characteristics are much better when compared with a conventional circular patch antenna of same radius without any slit.