Early treatment response assessment has become an import prerequisite in the selection therapy in childhood ALL. In this study we compare classical diagnostic factors and the significance of three simplified strategies, WBC count at day 7 and a simplified PCR methodology to minimal residual disease detection on days 14 and 28, to evaluate early treatment response in 84 consecutive children with ALL. The use of these simplified methods for the evaluation of early response, proved to be a good predictor of an unfavorable course in children with ALL and could be used as a stratification criterion in treatment protocols, specially in low-budget countries.