This was the first attempt to explore the floristic diversity of Koh valley, Chitral, Hindukush range, Pakistan.  Investigation of the area showed that the flora comprised of 310 genera and 540 species belonging to 95 families including 72 dicots, 14 monocots, 3 Gymnosperm and 3 Pteridophyte. Out of 540 species largest group was of Dicots (442), followed by Monocots (85), Gymnospems (9) and Pteridophytes consist of (4) species. Leading family of the research area according to species number was of Asteraceae with (70) species followed by Poaceae (44), Papilionaceae (43), Rosaceae (28), Lamiaceae (27), Polygonaceae (19), Apiaceae (19), Brassicaceae (18), Boraginacea (14), Caryophyllaceae (14), Ranunculaceae (13), Cucurbitaceae (11), Chenopodiaceae (10), Solanaceae (9), Salicaceae and  Scrophulariaceae (8) each,  Geraniaceae (7) and remaining families consisting of six, five, four, three, two and one species. Biological spectrum showed that the dominant group was of Therophytes with (225) species, followed by Hemicryptophytes (132), Geophytes (63), Megaphanerophytes (45), Chamephytes (42) and Nanophanerophytes (33). The leaf size spectrum was dominated by Nanophylls having (187) species, followed by Mesophylls (145), Leptophylls (111), Microphylls (60), Macrophylls (32) and Aphyllous with (5) species. Most of the plants shows phenology during summer season followed by spring, autumn and winter. According to altitude most of the plants flourish well at the range of 1600-2100m of the sea level. All the villages of the research area viz-a-viz., Kari, Ragh, Kuju, Koghuzi, istangol, Mori, Morilasht, Moroi, Prayet and Barenis showed very rich floristic composition and very suitable for plant growth. Due to increase in population growth the burden on vegetation is increasing on each passing days. The collected plant samples after dring and voucher numbering was submitted to the Botany Department University of Peshawar for future reference.

Key words: Ecological characteristic, Koh Valley, Floristic inventory, Hindukush range, Pakistan.