The approximate size of these bird is 13 or 14 cm.

The Rufous-gaped Hillstar is a species of bird in the trochilidae family and order Apodiformes and a weight of 8.5 to 9.2g. It has a green copper back with a rufous chin and malar area. Its throat and chest are iridescent blue, it has a brownish gray belly, coppery uppertail coverings, black underflow, obscure green sides and flanks. Its central and external rectrices are black and the rest white with dark grey margin.

It is found between 1500 and 2800 m above sea level, along the Pacific slope from the headwaters of the San Juan River on Cerro Tatamá in Colombia to the north-east of Peru, passing through the north-west and east of Ecuador.

The habitats are forest edges or margins of bodies of waters, such as lakes, rivers particular common near mountain streams.

It is a sedentary and territorial hummingbird that moves altitudinally at certain times of the year.