Field experiment was conducted during kharif season 2014 at Main Agricultural Research Station, UAS, Dharwadto study the allelopahtic effect of summer sunflower on growth and yield of succeeding kharif mungbean (Vigna radiata L.Wilczek) under varied sowing periods. Significantly higher seed yield of mungbean was obtained in kharif mungbean sownin previously summer fallow land (CS2-716 kg ha-1) compared to kharif mungbean sown in previously summer sunflowergrown land (CS1-593 kg ha-1). Among the sowing periods, the crop sown after one week of harvest of summer sunflower(D1) was recorded significantly higher seed yield (D1-904 kg ha-1) over other sowing periods except two weeks after harvestof summer sunflower (D2-837 kg ha-1) with which it was on par. This was followed by mungbean sown after three weeksof harvest of sunflower (D3-726 kg ha-1). The interaction effect of kharif mungbean sown after summer fallow at the date ofT1 (CS2D1-1038 kg ha-1) was recorded significantly superior over other treatment combinations.