During the semen cryopreservation, various biochemical and anatomical compartments in the sperm cells (acrosome, nucleus, mithochondria, axoneme, and plasma membrane) may be altered. Therfore, the first aim of sperm-freezing protocols is use of cryoprotectant agents in freezing medium in order to prevent lethal intracellular ice crystal formation and to reduce membrane damage during freezing-thawing. Although egg yolk is a major beneficial cryoprotectant for sperm freezing, in recent years there have been frequent arguments against the use of egg yolk, one of which is the wide variability of composition that makes it difficult to analyze the beneficial effects of a particular compound on sperm cryopreservation. Furthermore, egg yolk introduces a risk of microbial contamination, with the subsequent production of endotoxins capable of damaging the fertilizing capacity of spermatozoa. Regard these facts; Substitution of egg yolk with soybean lecithin may reduce these risks in freezing medium. Though a few studies have been performed on the effect of soybean lecithin in bull, to date evaluation of ram semen in vitro fertility after cryopreservation with use of soybean lecithin has not been studied. This study assessed the effect of 1% or 2% (wt/vol) soybean lecithin (L1 or L2) or 15% or 20% (vol/vol) egg yolk (E15 or E20) supplemented with 5% or 7% glycerol (G5 or G7) in a Tris-based medium for cryopreservation of ram (Oviss arries) semen. Semen samples were diluted with extenders and then frozen. The sperm parameters were assessed after thawing for motility, viability and acrosomal status. In vitro Fertility was recorded as cleavage, blastocyst and hatching rate. The analysis of variance (ANOVA) was used for comparisons of means. The mean of the treatments were compared using Duncan’s multiple range test (DMRT) and a confidence level of P 0.05 was considered to be significant. Although no significant difference was observed in pattern of acrosomal status, the best results in terms of sperm motility, viability and cleavage rates were observed with L1G7 (51.9± 4.8%, 48.1±3.5%, and 79.6±3.9%, respectively) and E20G7 (51.8 ± 3.8 %, 46.7 _ 2.9 %, and 72.9 _ 6.4%, respectively). Our results also showed that 1% lecithin and 20% egg yolk was superior to 2% lecithin and 15% egg yolk. In terms of cleavage rate, 7% glycerol was superior to 5% glycerol. No significant difference was obtained between groups in terms of blastocysts rate per cleaved embryo and hatching rate. Therefore, we concluded that the optimal concentration of lecithin and egg yolk is 1% and 20%, respectively, along with 7% glycerol. In addition, our results suggest that lecithin can be used as a substitute for egg yolk. Keywords Cryopreservation, Freezing medium, Soybean lecithin, Sperm parameters, IVF .