The study examined the market concentration and efficiency of sweet melon and water melon in Gombe and Bauchi States, Nigeria. Multi-stage sampling technique was used to select 300 sweet melon and water melon marketers from 18 markets, among which 165 marketers were selected from Gombe and 135 from Bauchi States. Data were collected using structured questionnaires. Descriptive and inferential statistics were used for the analysis. The gini-ratio analysis indicates that sweet melon and water melon retail marketers handled larger quantity of the commodities which amounted to 26,562 and 34,871 respectively. The same category of marketers also recorded the higher gini-ratio of 0.14 and 0.17, respectively. The marketing efficiency results revealed that retail sweet melon marketers recorded the highest efficiency of 53.08%. Conclusively, both sweet melon and water melon markets were highly efficient and concentrated, implying that there is perfect inequality in the distribution recorded which might be as a result of limited information access on prices and products availability. The study recommends the establishment of collaboration between private and public research and development programs to improve management practice, particularly the use of new available technology for time disposal and efficient marketing of sweet melon and water melon in the study area.