This study investigates the housing conditions and deforesting in Caconde and São José do Rio Pardo, neighbouring towns located in the northeastern region of the State of São Paulo, Brazil. These localities have had different dwelling infestation rates by Panstrongylus megistus and they also show distinct socioeconomic development. The housing conditions were studied by the analysis of data collected during the 1970's by the Superintendência de Controle de Endemias (SUCEN), a government agency. Aerial photographs taken during flights performed by the Agricultural Department of the State were used to analyse the deforesting. The socioeconomic analysis was based on Agricultural Census and interview with agronomic officials. The study showed more precarious housing conditions in Caconde than in São José do Rio Pardo. It was related to lower socioeconomic development in Caconde, confirming a trend showed by previous studies. The deforesting was more intense in São José, where socioeconomic development has been higher and the infestation rates were lower, what demonstrates opposite behaviour between the two determinants in these towns. The links between deforesting and higher socioeconomic development can also be showed by the relation between productive activity and destruction of the natural agricultural covering. It is emphasized that the tendency of opposite effect of the deforesting did not change the final result, that is, the confrontation of these determinant forces resulted in higher infestation rates in Caconde than in São José do Rio Pardo. The existence of these opposite trends between the determinants disclosed therefore more complexity in the infestation process of P. megistus, although the final result was not reverted changed.