Plant diversity of the Rono Hills was studied during 2004-2005. All trees > 10 cm dbh at 1.3 m, shrubs and herbs (including grasses) were recorded. The total and relative values of each species for density, diversity, dominance and Importance Value Indices were calculated. A total of 138 species belonging to 122 genera under 66 families and 3 unidentified species were recorded. The Importance Value Index (IVI) of some ecologically significant trees, shrubs and herbs are Callicarpa arborea (24), Lantana camara (51) and Ageratum conyzoides (19), respectively. The total basal area of trees was 17.84 m2 ha-1. The highest Shannon -Wiener diversity index was recorded for trees (3.66) and minimum for herbs (3.60). The human interference needs to be monitored and controlled for the conservation of forest cover of ecologically fragile foothills.