The serum concentrations of inflammatory (Interleukin-1 beta, Tumor necrosis alpha, Interleukin-6) and regulatory cytokines (Interleukin twelve) have been studied in ten AIDS cachectic patients and compared to a control group. A cytokine imbalance, and peculiarly a significant increase in proinflammatory cytokines (Interleukin-1, Interleukin-6, Tumor necrosis Factor alpha) and a decrease in regulatory cytokines such as Interleukin-12 were found. A significant correlation resulted between weight loss and Interleukin-1 beta and 6. A negative correlation between Interleukin-1 and 12 was noted, indicating that this last cytokine has an important regulatory role also in advanced state of the disease.