Powdery scab affects most potato production zones in the world. The causal organism Spongospora subterranea f. sp. subterranea forms galls in roots and lesions on tubers during its replication. Recent researches suggest that S. subterranea could cause harmful effects on the host plant and potentially on yield.In order to quantify the disease impact on plant growth and yield, potato Solanum tuberosum ssp. andigena, cv. Diacol Capiro was grown in a soil infested with S. subterranea and compared to a healthy control soil. Data was taken at the flowering stage and at harvest. S. subterranea caused a plant length reduction of 23%, a foliar dry weight reduction of 32% and a tuber weight reduction of 30%, whereas S. subterranea did not reduce the number of tubers or stems.