Field surveys were undertaken to examine disease occurrences in major crops in Paraguay. The surveys covered 16 prefectures during the period 1986 to 1988. In the rice plants sampled, 11 species of fungal diseases were identified, while no bacterial and viral diseases were observed. Causal fungi of 3 species were recognized to be the most serious, and widely spread. In the 14 crops other than rice, including wheat, citrus, vegetables, root crops, industrial crops and flowers, more than 50 diseases brought about mostly by pathogens were identified. Among those diseases, 68% (35) were caused by fungi, 20% (10) by bacteria, 10% (5) by viruses, and 2% (1) by non-parasitic causes.