To investigate the efficiency of application of «male effect» on Ascanian Merino sheep at non-breeding period and the influence of additional treatment with progesterone «P–» and «P+» groups were formed. Animals of «P+» group were injected subcutaneously with 1 ml 2.5% oil solution of progesterone once for 5 days prior to the beginning of contact with ram. Ewes had contacted with rams 1,5–2,5 hours per day during the period from 1st to 10th and from 15th to 22nd days of experiment. During the period from 1 st to 10th days no sheep showed a heat. During the period from 15th to 22th days in «P–» group 29,4% animals had heat, in «P+» – 68,8%. Eventually in group «P–» 11,8% animals lambed (or 40% from heated), in «P+» – 43,8% (or 63,6%). Results indicated that in nonbreeding period Ascanian Merino sheep moderately positively respond to application of «male effect» and additional treatment of animals with progesterone significantly increases the quantity of heated and lambed animals, number of lambs per ewe.