Energy budget of mysid shrimp, Neomysis intermedia in Lake Kyongpo was determined at constant temperature (2$0^{circ}C$). Energy used by reared mysids were calculated from data on feeding, growth, molting, reproduction, and metabolism. The Energy used by growth of juvenile and adult were 6.87 cal in females of 8.55mm in length, and 5.67 cal in males of 7.53mm in length, respectively. Molting losses were estimated to be 0.46 cal in females and 0.38 cal in males from juvenile to adult. Energy used in respiration were estimated to be 48.48 cal in females and 36.45 cal in males from juvenile to adult. The energy intakes from feeding were 84.15 cal in females and 67.09 cal in males from juvenile to adult. Energy losses by excretion were 10.36 cal in females and 6.46 cal in males. Thus, females assimilated 86.65% and males 81.99% of assimilated energy in somatic growth. The gross growth efficiencies (k1) showed 8.71% for females and 9.02% for males and the net growth efficiencies (k2) showed 10.05% for females and 12.36% for males. Maintenance costs were estimated at 66.48% of assimilated energy in females and 66.26% in males. Molting losses among the energy assimilated from juvenile to adult were estimated to be 0.63% in males and 0.69% in females.