A new procedure is presented for estimating the crop coefficients for cotton, using a drip-irrigated field plot and neutron probe readings. Two seasons of data with uniform, near-normal irrigation produced crop coefficients that fit very closely to data obtained from a previous experiment with a complicated 6-level application rate. The peak crop coefficient for use with an evaporation pan was 0.88, and the peak for use with the Penman equation was 1.14, both comparing favorably with values found in the literature.