A study on the population behavior of Amblyomma cajennense and Amblyomma dubitatum larvae, nymphs and adult free-living stages was carried out in Coronel Pacheco County, Minas Gerais State, Brazil, a spotted feverendemic area from May 2006 to April 2008. Larvae of Amblyomma sp. were collected from pasture using the technique of drag sampling with flannelette during May to October 2006, starting from February 2007 to November 2007 and starting from March 2008. Well-defined peaks of populations occurred in May 2006, April-May 2007, April 2008 and October-November 2007. Nymphs were captured throughout the year by the use of traps with carbon dioxide and peaks populations were observed between June and November. Adults occurred throughout the year with an increase in population density from October to March and from August to April for A. cajennense and A. dubitatum, respectively, during the two years of experiment. Were identified peaks populations in October- November 2006 and 2007, January-February 2007 and 2008 for A. cajennense and October-November 2006 and 2007, February-April 2007 and 2008 for A. dubitatum. These results show that a different seasonal pattern for freeliving stages of A. dubitatum regarding the population of A. cajennense in the study area.