Effect of lamb age, transport stimulation and repeated hormone superovulation on the number of collected oocytes were determined. Effect of the culture medium containing ethylenediaminetetraacetic acid (EDTA) on the development of embryos produced in vitro from lamb oocytes was also investigated. Results indicated that the mean numbers of collected and available oocytes (oocytes with compacted cumulus cells, evenly granulated ooplasm and morphologically normal) from 6- to 8-week-old lambs were 60.8±13.9 and 58.2±12.3, respectively. These figures were higher than those obtained from 12- to 14-week-old lambs (27.3±5.1 and 26.0±4.9) (P<0.05). Stimulation by transportation didn't decrease the number of collected oocytes from the superovulated lambs (P>0.05). However, the number of collected oocytes in the repeated superovulation group was significantly reduced, compared with the control group (P<0.05). The embryonic culture medium supplemented with 10 μmol/l EDTA highly improved the development capability of the embryos from lamb oocytes (P<0.05). Healthy lambs were born following embryo transfer.