The objective of this study was to investigate the effect of partial substitution of clover hay by tomato vines hay (DTV) at three levels in lamb rations on their growth performance. Twenty-four Barki lambs with initial weight 28±1.5 kg and aged 6-7 months were randomly divided into four similar groups (6 lambs in each group) according to their LBW and were used in a feeding trial lasted 97 days. Lambs were fed with 0, 10, 20 and 30% of DTV as instead of CH in ration (T1) that served as control and the tested rations T2, T3 and T4, respectively.Results indicated that DM, OM and NFE digestibility did not differ significantly among all groups. Moreover, CP, CF and EE digestibility were decreased by increasing the levels of DTV in the tested rations. Feeding values of TDN were significantly (P≤ 0.05) decreased with increasing levels of DTV meanwhile, DCP values were not significantly differ among treatments. Daily gain was insignificant decreased with tested rations T2 and T3, but decreased (P≤ 0.05) significantly with tested ration T4, in comparison with those of control one (T1). All blood serum parameters were not significantly affected by the dietary treatments. The best economic efficiency was associated with tested ration (T3) that having 20% DTV in replacing with CH. It could be concluded that DTV can be used up to 20% as substitute of CH  in lambs rations, without any adverse effects on productive performance, health status and reducing  the environmental pollution.