In this study, 86 children (58 initial ALL and 28 children with relapsed disease) were investigated for lung resistance protein (LRP) and multidrug resistance related protein (MRPI)-mRNA expression by semiquantitative RT-PCR. The majority of investigated cases demonstrated variable LRP and MRP1 mRNA expression, when normalized for beta-microglobulin expression. LRP and MRPI mRNA expression may be coordinately regulated, as expression of both transcripts was found to be significantly correlated (p = 0.0001). No differences of LRP and MRP expression were observed between initial and relapsed stage patients (LRP: p = 0.89 and for MRP: p = 0.09). The prognostic value of both resistance mechanisms was subjected to Kaplan-Meier analysis for event-free survival. For this analysis the patients were divided into groups with high or low LRP or MRPI mRNA expression by utilizing the median value as the cut-off point. Overexpression of both resistance mechanisms had no prognostic significance in our retrospective study (log-rank test for LRP: p = 0.12 and for MRPI: p = 0.95), however, patients who showed high LRP expression exhibited a lower tendency of remaining in continuous first remission.