This research was carried out at Agronomy Department laboratory, Faculty of Agriculture, Mansoura University, Egypt. The germination experiments, which were set up as factorial experiments designed in randomized complete block design with four replicates. The purpose of the thesis was to find out the influence of different temperature treatments plus scarification and the same temperature without scarification on the reduction of percentage of hard seeds and improvement other germination parameters in five alfalfa cultivars (Siriver, Sewa1, Ismailia1, Balady1 and El-Wady El-Gaded1). The trial contained nineteen different treatments: this research i. e control treatment; 5 hours +5°C; 5 hours +10°C; 5 hours +20°C; 5 hours +40°C; 5 hours +80°C; 5 hours -5°C; 5 hours -10°C; 5 hours -20°C; 2 hours -80°C and the same treatments plus sandpaper scarification (s) except control treatment. Alfalfa cultivars significantly differ in averages of hard seed percentage, percentage of abnormal seedling, percentage of dead seed, germination percentage free of hard seed, normal germs percentage, energy for germination percentage, coefficient velocity percentage, mean germination time (MGT) by days and value of the vigour percentage. Balady1 cultivar had only positive effects in all studies characters while; El-Wady El-Gaded1 cultivar had only negative effects on all germination parameters under study. Break down dormancy treatments significantly differed in all germination parameters under study. The two treatments, -80°C+ (s) and -80°C were very efficient since they reduced the percentage of hard seeds in comparison with the control by70.455 % and 63.636 %, respectively while their influence on dead seed percentage was completely different. The treatment with -5°C had only positive effects on other germination parameters that were reflected in the highest values for germination energy and germination percentage of free of hard seed.