A three- year (1993-1995) field test was conducted in south Alabama on a sandy coastal plain soil to evaluate the response of cotton (Gossypium hirsutum L.) to the source, rate and timing of sulfur fertilizer applications. Sulfur was applied as either ammonium sulfate, elemental sulfur, potassium sulfate, potassium thiosulfate, or K-Mg-sulfate at rates of 0, 10, 20 and 40 lb sulfur/acre. All sources were broadcast applied pre-plant and ammonium sulfate was also applied at first square. Seed cotton yields were increased by the application of sulfur during all three years of the test. Yields peaked at approximately 20 lb sulfur/acre. Averaged across sources, an application of 20 lb sulfur/acre increased seed cotton yields by an average of 26% as compared to the no sulfur check treatment. Applying sulfur pre-plant versus first square did not affect seed cotton yields in 1993 or 1995. In 1994, pre-plant applications of sulfur gave higher yields as compared to sulfur applied at first square. Seed cotton yields were not affected by the source of sulfur during 1993 or 1995. In 1994, ammonium sulfate and K-Mg-sulfate produced slightly higher yields as compared to the other sources. Lint quality in 1993 and 1994 was not affected by any of the sulfur treatments.