A low-voltage programmable frequency divider with wide input frequency range is fabricated in standard 0.18µm TSMC RF CMOS technology and presented in this paper. Considering the frequency division ratio of dual-modulus prescaler is relatively smaller, a programmable divider with full custom design is used to increase the frequency division ratio and the maximum operating frequency. The frequency division ratio of the programmable frequency divider covers from 64 to 255. And the measured results show that the programmable divider works correctly when the input frequency varies from 0.5 GHz to 6.0 GHz, with 1V supply. Besides, the power consumption is 3.5 mA at the maximum frequency of 6.0 GHz.