Dysmotility and delayed emptying of the stomach have been reported in patients with chronic renal failure (CRF). The aim of this study was to investigate whether gastric myoelectrical activity was impaired in patients with CRF using electrogastrography. The electrogastrogram (EGG) was recorded in 24 symptomatic patients with CRF (15 with diabetes) and 12 normal subjects. Two 30-min EGG recordings before and after a test meal were analyzed using spectral analysis methods. It was found that patients with CRF showed a significantly lower percentage of normal 2-4 cpm slow waves in both fasting and fed states in comparison with healthy controls (in fasting state: 88.9 +/- 2.5% vs 67.4 +/- 6.6%/63.2 +/- 7.0%, P < 0.01; in fed state: 89.6 +/- 1.8% vs 64.6 +/- 6.2%/62.0 +/- 8.3%, P < 0.01; controls vs diabetic patients/nondiabetic patients). Both patient groups showed a significantly higher prevalence of the abnormal EGG, which was defined as the percentage of 2-4 cpm slow waves lower than 70% (fasting state: 8% vs 60%/56%, P < 0.01/0.05; fed state: 0% vs 53%/56%, P < 0.005/0.002; controls vs diabetic patients/nondiabetic patients). No significant difference was observed in the regularity of the gastric slow waves between the two patient groups. The healthy controls showed a significant increase in the dominant power and frequency of the EGG after the test meal. However, this increase was absent in the two patient groups. It was concluded that patients with chronic renal failure have abnormal gastric myoelectrical activity, including impaired regularity of the gastric slow wave and a failed increase in the power of the EGG at 3 cpm. Electrogastrography is an attractive noninvasive method for the study of gastric motility in patients with severe chronic renal failure.