Several pharmacological agents have been found to alter systemic concentrations and/or the activity of different cytokines via a variety of mechanisms, including changes in biosynthesis, secretion, and/or stability. Pentoxifylline (PTX), which is a methylxanthine derivative for example, has multiple effects on the immune system, but inhibition of pro-inflammatory cytokine release predominates. In this study we aimed to evaluate the influence of PTX on plasma levels of tumor necrosis factor (TNF) alpha and interleukin (IL)-6 in newborn infants with sepsis. The study included 20 infants with neonatal sepsis. In all subjects blood samples for serum C-reactive protein, TNF alpha and IL-6 determinations were received before giving PTX and at the 12th and 24th hours following PTX. In addition, white blood cell was counted before giving PTX and on the 3rd and 7th day following PTX. The infants were randomly divided into two groups. Firstly, PTX was used in infants who were successively admitted to the clinic and the subsequent infants were accepted as a control group. Of 20 infants, 13 infants received PTX and seven infants did not. We did not find any difference in the leukocyte count, serum C-reactive protein level, TNF alpha and IL-6 levels between the two groups of patients (P>0.05). While three infants died in the group of receiving PTX, death was not recorded in the group of non-receiving PTX (P>0.05). Our findings showed that PTX treatment did not affect leukocyte counts, serum CRP levels, TNF alpha and IL-6 levels and death ratio in newborn infants with sepsis. The last result may be due to the fact that the number of patients in the study was very small. We think that more extensive and controlled studies should be performed about this subject.