Cytokines may be implicated in the pathophysiologic mechanisms of preterm and term labor. Many studies indicate cytokines as predictors of preterm delivery and explain partially mechanism of preterm uterine contractions. Complicated relations between mediators in systemic fluids of a fetomaternal unit require further explorations. The right diagnosis and management require better understanding of these relationships. OBJECTIVE The comparison of IL-1 alpha, IL-1 beta, IL-6 and IL-8 levels in maternal serum and amniotic fluid in term and preterm labor complicated by PROM. METHODS In 44 patients in premature labor with PROM (group I) and 33 patients in labor at term with PROM (group II) cytokines levels were estimated one time in amniotic fluid: just after PROM, and two times in maternal serum: just after PROM and during labor. RESULTS Amniotic fluid cytokines levels were significantly higher in group I than in group II. Maternal serum cytokines concentrations of IL-1 alpha and IL-1 beta in group I were significantly higher than in group II. IL-6 level was significantly higher in group II than in group I. In both groups maternal serum IL-6 levels during labor significantly increased in comparison to IL-6 levels just after PROM. No correlations between amniotic fluid and maternal serum cytokine levels at PROM were observed. CONCLUSIONS Higher amniotic fluid cytokines levels in patients with preterm labor complicated by PROM than in labor at term with PROM indicate possible differences between PROM mechanisms in preterm and term labor. The increase of IL-6 level during labor can be related with the possible role of this cytokine in the immunological mechanism of the labor beginning. No relationships between amniotic fluid and maternal serum levels of investigated cytokines in PROM suggest the presence of the barrier stopped cytokines transfer by the placenta and the complete separation of these two compartments.