The efficacy of sodium laurel sulfate as a defaunating agent, as well as effect of defaunation on body confirmation changes, wool yield and fibre characteristics, were evaluated in growing lambs in a 90-day feeding experiment. Forty-five Malpura male weaner (90-day old) lambs were divided into three equal groups: defaunated, refaunated and faunated. The lambs of defaunated and refaunated groups were defaunated by oral administration of sodium laurel sulfate at the rate of 8 g/100 kg liveweight as a 10% aqueous solution. Six days after defaunation, all the lambs of the refaunated group were refaunated by inoculation of 100 mL rumen content per lamb drawn from a normal faunated sheep. All the experimental lambs were maintained under stall feeding on a complete feed containing 50 : 50 Pala (Ziziphus nummularia) leaf and concentrate. Treatments did not differ in intake of dry matter, digestible crude protein or digestible energy. Body height and paunch girth were greater (P < 0.01) in defaunated compared to refaunated and faunated lambs. With similar dry matter intake in the three experimental groups, liveweight gain, feed conversion efficiency and wool yield were higher (P < 0.01) in defaunated lambs. The wool fibre diameter and medullation percentage were higher (P < 0.01) in defaunated than refaunated and faunated lambs. It was concluded from the study that, with similar dry matter intake and plane of nutrition, the growth rate, feed conversion efficiency and wool yield were higher in defaunated lambs, as compared to refaunated and faunated lambs. Higher paunch girth in defaunated lambs resulted in a pot-bellied appearance of the animals.