Objective. To describe the use of health services and associated factors in health care centers of the Ministry of Health of Peru (MINSA). Materials and methods. An ecological study was conducted with information from outpatients placed in all health centers from all Regions at the national level from 2009-2011. The use of health services was defined by the proportion of outpatient and the total population. This variable was compared by gender, age group, geographic area, and calendar year. Chi-square test was performed to compare proportions between the different layers. In addition, linear regression was performed to determine factors associated. Results. In this period of time there was an increased number of health care centers and health insurance coverage, but the use of health services decreased from 43.3% (2009) to 40.3% (2011). An increased use by female residents, age group of 0-29 years old and residents from the southern region was found. A multivariate analysis was conducted and factors associated with use of health systems were geographic area, and calendar year. Conclusions. Use of health services is not associated to the increased number of health centers nor the access to health insurance, but it is associated to individual factors or health system-related factors that should be evaluated in future studies.