Application of Liquid Organic Fertilizer Fish Waste on Cucumber Plants (Cucumis Sativus L). This study aims to determine the application of fish waste POC on the growth and yield of cucumber plants and to determine the correct POC dose of fish waste for optimal cucumber growth and yield. The research design used was a single factor randomized block design (RBD) consisting of 7 (seven) treatment doses of fish waste POC, namely: P0 = no treatment (control) = 0 lt/ha; P1 = 500 lt/ha; P2 = 1000 lt/ha; P3 = 1500 lt/ha; P4 = 2000 lt/ha; P5 = 2500 lt/ha; P6 = 3000 lt/ha. Growth variables observed were number of leaves and leaf area, while yield variables observed were number of fruits per plant, fruit length, fruit diameter, and fruit weight per plant. POC application of fish waste had a significant effect on the average percentage increase in the percentage of leaves by 8.73%, leaf area of 8.73%, number of fruits per plant 35.05%, fruit length 4.65%, diameter 3.79%, and fruit weight per plant 30.05%. The POC dose of 3000 lt/ha fish waste gave optimal growth and yield, namely with 6 leaves, 316.18 cm2 leaf area, 6.71 fruit per plant, 20.96 cm fruit length, 4.61cm fruit diameter and fruit weight per plant 2.69 kg.