From June to November 1967, a study on channel catfish, lctalurus punctatus (Rafinesque), in Mud Lake, Utah Co., Utah was undertaken. The objectives were (I) to estimate if channel catfish are increasing or decreasing in Mud Lake, (2) to estimate the mean size of adult channel catfish in Mud lake, (3) to determine which environmental factors effect the catch of channel catfish, and (4) to determine if the channel catfish in Mud lake are residents year round. A total of 310 mature channel catfish and 920 carp were collected with four hoop nets. Two fingerling were captured by seining. Ratios between carp and channel catfish over a 17 year period had been established which indicated a possible increase in the channel catfish population. With the exception of the fingerIings all channel catfish captured were at least 36.8 cm long with an average of 50.2 cm. A comparison between environmental factors (water temperture, turbidity, water level, and barometric pressure) and the catch showed that only water temperature changes had a statistically significant influence. Large catches during June, July, August, and September were recorded. In later months the numbers of fish captured decreased and no channel catfish could be seen when tho water cleared. It appears that channel catfish utiIize Mud Lake only during the summer.