Food problem and availability of fodder are real development’s brakes of breeding in Sahel. The aim of study is to determine productivity of alfalfa grown in rainy season. It was carried out on experimental site of Faculty of Agronomy in Abdou Moumouni University (Niamey). Experimental set-up consists of 8 plots of 3m x 2m with inter-plot spacing of 1 m. A spacing of 20 cm by 20 cm was used when sowing. Water was added when needed and 100 kg NPK per hectare was added after first cut. An emergence rate of 15.52% was obtained respectively, number of branches reached 4 ± 2 branches at 1st cut. Height of plants was 41.33 ± 10.31 cm 45 days after sowing; 41.67 ± 9.79 cm at 2nd cut in 20 days and 29.5 ± 7.63 cm at 3rd cut in 20 days. The yield (kg DM / ha) at first cut is 510.7 kg. At second cut, it is 1394.95 kg and the third cut yield is 944.42 kg. The average production in 85 days is 2850.07 kg DM / ha. This culture is promising, given conditions and means used during trial. It can produce better when put in best conditions.