Twelve cotton varieties and hybrids were grown on 40-inch and 32-inch rows under trickle irrigation. The 32-inch rows were on 64-inch double beds, supplied with a single trickle line in the center. This amounted to 33% less line/A as compared to that used for 40-inch rows supplied with a line under each row. Emergence and early growth was better on the twin 32-inch rows. By the end of the season, however, the 40-inch rows were slightly taller. There was extreme variability in growth between sections of the field, which may have been due to differences in soil moisture holding capacity at a critical point in mid-season when the supply pump was lost for several days. More vegetative genotypes like Acala 1517-75 were pushed close to their responsive limits by use of optimal moisture and 163 units of N. Overall yield for the entire experiment was 1780 Kg/ha (3.17 bales/acre) . Hybrid NX-1 was the highest yielder in the 32-inch (81 cm) rows at 2000 Kg/ha, while Acala 1517-75 was the top yielder in 40-inch (102 cm) rows at 1947 Kg/ha. Adjacent comparison plots of the same row spacings and strains yield only slightly less under flood irrigation.