To study the floristic composition of weeds in greengram, 50 fields were surveyed in Hisar, Sirsa, Bhiwani, Mahender Garh and Fatehbad districts of Haryana state during July-August, 2011 and 23 fields were surveyed for blackgram in Shiwalik foot hills region of Panchkula, Ambala and Yamuna Nagar districts of the state during August-September, 2012. Weed flora in greengram was more diverse as compared to blackgram. Twenty-two weed species (5 grassy, 3 sedges and 14 broad-leaved) belonging to12 families were found dominant in greengram, where as in blackgram only 11 weeds of 7 families were found to be very aggressive. Broad-leaved weed Digera arvensis (L.) of family Amarthanceae was the most dominant and aggressive weed of both crops with a relative density and frequency of 511% and 86% in green gram whereas in blackgram it was 38% and 96%, respectively.  Dactyloctenium aegyptium (L.) was the most dominant grassy weed with IVI values of 24.5 and 22.6 in greengram and blackgram, respectively. Important broad-leaved weeds found in greengram were: Trianthema portulacastrum, Mollugo distachya, Cleome viscosa, Cucumis callosus, Corchorus tridens, Corchorus aestuans and Tribulus terristeris, whereas  in blackgram Commelina benghalensis, Physalis minima, Solanum nigrum and Chorchorus olitorious.