Gymnophthalmidae is a family of Neotropical lizards from which its ecology has been widely studied in the lowlands. However, the life history of Andean species is still unknown, being most of these species apparently tolerant of anthropic habitats. The objective of this study is to describe some aspects of the ecology of one of the species of this family, Riama striata, a lizard found in a highly urbanized area in the Eastern Cordillera of the Colombian Andes. I describe microhabitat use, shelter preference, activity patterns, population structure and sexual dimorphism of the species. Riama striata uses both artificial and natural substrates that are mainly microhabitats of rock and concrete, and males prefer bricks even though this is the least frequent refuge available. The species has a bimodal diurnal activity, particularly on sunny days. It is sexually dimorphic in the size of the head; males have larger heads. There is a high abundance of individuals, with a greater number of females and juveniles than males. These results, together with those of other Andean species contrast sharply with the studies in gymnophthalmids and alopoglosids of the lowlands and raise new hypotheses about the ecology and life history of these lizards and how they respond to the effects of anthropic impact.