The Rufous-shafted Woodstar is a very small hummingbirds even when compared with other woodstars, like the Purple-throated. Their plumage is also less colorful, consisting of an olive green back, brown wings and cinnamon belly. The female has has olive green on the top of the head, a thin white line that stems from the eye, then a dark ear patch, and a white throat with a dark line on the center. The male has a glittering purple gorget and lacks the cinnamon belly, which is metallic green instead. Like all other woodstars, this species is very small and flies in a bee-like fashion, with swifter movements than larger hummingbirds.