The floristic diversity of Handuzu Natural Park and Environs as a protected area within Kackar Mountains chain, situated in Guneysu and Ikizdere counties of Rize (Turkey) was studied. Overall, 517 taxa belong to :352 genera and 104 families were determined. Twenty-three of these taxa are represented in division Plericlophyta while 494 of them are in division Spermatophyta. Ten of Spermatophytes are in subdivision Gymnospermae and 484 of them are in subdivision Angiospermae. 89 of Angiosperms are in class Liliopsida while 395 of them in class Magnoliopsida. The endemism ratio in the study area is 4.25% (22 taxa). Phytogeographic elements are listed in order as: multiregional-unknown phytogeography root 47.4% (245), Euro-Siberian 47.2% (244), Irano-Turanian 2.1% (11), and Mediterranean 3.3% (17). The life spectrum of taxa is as follows: Hemicryptophytes 48.7% (252). phanerophytes 16.1% (83). therophytes 15.7% (81), chamaephytes 10.4% (54). and cryophytes 9.1 %, (47). The richest families in taxa are Asteraceae (52). Poaceae (35). Rosaceae (31), Fabaceae (25), and Lamiaceae (24). In the study area 22 taxa were found as threatened taxa at. different threatened levels. The results of the study was compared with the results of 10 studies carried out in Rize and neighboring cities.