Abstract: Field experiment was conducted during summer 2003 at Malakandher Research Farm, NWFP Agricultural University Peshawar, Pakistan to study the response of maize hybrids to various levels of potassium and irrigation frequencies. Statistical analysis of the data revealed that potassium @ 150 kg acre-1 increased days to tasseling, grain weight cob-1, 1000 grain weight, grain yield and biological yield. Different hybrids respond significantly different for all the parameters. Maximum 52 days to tasseling, 152.9 g grain weight cob-1, 321.2 g thousand grain weight and 2790 kg acre-1 grain yield was observed from plots irrigated weekly. However germination percentage and emergence m-2 were not affected significantly by irrigation. Silking delayed by fortnightly irrigation. Monsanto 922 performed better than Pioneer 3025, Pioneer 3062 and Azam. Interaction between hybrid and potash showed that Monsanto 922 gave maximum grain yield 3676 kg acre-1 when given 150 kg potash acre-1. Monsanto 922 also obtained maximum biological yield with 150 kg K acre-1 and weekly irrigation.