The community composition and distribution of weed flora in the rice field agro-ecosystems of Kashmir valley was studied. The investigation revealed a presence of 64 species of weeds including 41 dicotyledons, 20 monocotyledons and 3 pteridophytes from the 6 representative sites located in different administrative zones of the valley. The sites of study included Kupwara, Bandipora, Budgam, Srinagar, Pulwama and Anantnag. Monthly samplings were performed throughout the fallow as well as vegetation phase. The taxocoenosis was inclusive of 23 families. Gramineae was the most dominant family represented by 11 species of weeds. Qualitatively Bandipora was the most dominant site recording a total of 57 species. The overall qualitative dominance pattern exhibited by the study sites was: Bandipora (57 spp.)>Kupwara (55 spp.)>Budgam (54 spp.)>Pulwama (52 spp.)>Srinagar (50 spp.)>Anantnag (46 spp.). Biodiversity was calculated through Shannon-Wiener diversity index (H’) and Margalef’s richness index (d). The results were indicative of the richness of diversity at Bandipora site (H’ = 3.755; d = 9.527) whereas, Anantnag (H’ = 3.271; d = 7.670) was marked as the least diverse site. Anthropogenic disturbances and climatic factors seemed to govern the growth patterns of the flora. The importance of rice field ecosystems as significant contributor of biodiversity in the region was recognized.