This study was conducted to determine the effect of varieties and maturity stages on yield, quality and nodulation of alfalfa in Isfahan . The experiment was conducted at the agricultural research station Isfahan University of Technology located at Lavark Najaf–Abad in October 2004. Treatments were replicated three times in a randomized split plot in time design, with cultivar as the main plots and maturity stages (50% bud, 10% bloom and 50% bloom) as the subplots. Plant height, dry matter percentage, dry matter yield and leaf to stem ratio were recorded at each cut and maturity stage. Crude protein, acid detergent fiber and neutral detergent fiber were also measured. In fourth cutting, sampels were collected from five maturity stages including vegetative growth (two week aftar regrowth), 50% bud, 10% bloom, 50% bloom, and 100% bloom from Rehnani Isfahan. Crude protein, acid detergent fiber, neutral detergent fiber, ash, nutrient concertration and crude lipid were measured. A greenhouse study was conducted to determine nodulation of varieties. There were significant differences between varieties and maturity stages on all of the treats. Comparison of the average of five cuttings revealed Cody had the highest plant height, dry matter percentage and protein yield. Furthermore, dry matter yield and leaf yield of Cody and Bagh Malek were the highest. First cutting produced the highest and the fourth cutting produced the lowest dry matter yield. In the first cut Composit Rehnani, at the second Bagh Malek, at the third Cody, at the fourth Nik Shahri and at the fifth Bagh Malek had the highest dry matter yield, respectively. In 50% bud stage, Cody (18.34 ton/ha), in 10% bloom and in 50% bloom, Bagh Malek (22.49 and 26.63 ton/ha) had the greatest dry matter yield, respectively. Famenin had the greatest nodul per plant. Alfalfa at the 50% bud stage, had the highest crud protein and the lowest acid detergent fiber and neutral detergent fiber. In 50% bud stage, and in 10% bloom, Rehnani Isfahan, and in 50% bloom stage, Cody had the highest percentage of crude pritein. Rehnani Isfahan had the least acid detergent fiber and neutral detergent fiber. Nutrient concentration decrease with advanced in maturity exept of boron and phosphorus. Dry matter yield had a positive correlation whith leaf yield (r= 0.96**) and stem yield (r= 0.97**). Negative correlation were observed between dry mater yield and leaf to stem ratio (r= -0.43**). Crude protein percentage had a negative correlation with acid detergent fiber and neutral detergent fiber percentages (r= -0.87**, -0.85**), respectively. Positive correlation between acid detergent fiber with neutral detergent fiber (r = 0.87**) were observed. Cody and Bagh Malek were the superior cultivars based on total yield and quality.