The sperm quality index (SQI) available per equal volume of AI doses (mL), seems to be a promising predictor of the Muscovy semen fertilizing ability. The proposed SQI=N.M/100.(100-A)/100 includes the number of spermatozoa per an AI dose (N), the percentages of sperm motility (M) and percentages of live normal spermatozoa (100 – abnormal spermatozoa). The relationship between SQI and the fertility of mule eggs was rp= 0,437 (p<0,001). The semen was collected individually from 6 one-year-old Muscovy drakes by the teasing method two times per week. For individual evaluation semen was collected ten times in total from each male. In the fresh semen the following traits were estimated: ejaculate volume, sperm mobility, concentration, pH, methylene blue reduction test, abnormal and dead spermatozoa. Individual semen was inseminated into 6 Peking ducks in a group per treatment (n = 6 groups).