Mating, oviposition, post-oviposition, development, and generation period of the two land snail species Monacha cartusiana (Müller) and Eobania vermiculata (Müller) were studied in the laboratory of Zoology & Agricultural Nematology Department, Cairo University, Egypt during the two seasons of 2003/4 and 2004/5. Data revealed that mating is essential for both snail species to lay eggs, thus it occurs when snails reached their sexual maturity (from adulthood till mating) during a period averaged 190.3 and 228.6 days for M. cartusiana and 231.6 and 568.3 days for E. vermiculata after adulthood in the two different seasons respectively. The other biological aspects had been evaluated and mention in this study. it had been studied the survey, population density, effect of photoperiod as well as effect of dryness on both terrestrial snails.