Background: the intestinal parasitism is common infections in the world and of higher prevalence in the poor community of developing countries. Until ending of decade of eighties, Blastocystis hominis is not reported in a routine way, being only a differential diagnostic problem; but in the nineties by means of an appropriate diagnosis increase its prevalence of 1.5 to 10 % in developed countries and with 30 to 50 % in developing countries. Objective: to compare frequency of Blastocystis hominis in preschoolers from an urban area and rural area of Cartagena de Indias and its relation with signs and symptoms and risk factors during the year 2013. Materials and methods: 286 samples of feces of children between 1 and 5 years old from an urban area (Crespo) and rural area (La Boquilla small town) were analyzed by serial coprological technique. Results: were found parasites in 38.5% (55/143) of children from urban area and 79% (113/143) of children from rural area. It was found association between presence of parasites with origin of children ( X 2 = 48.53; p<0.0001). We reported a frequency of 51.1% de B. hominis in an urban area and 44.8 % in a rural area. Conclusions: the absence of monitoring and control of cases suggests the need to formulate and implement measurements guided to improve the quality of life in studied areas.