The present study involved the biochemical characterization of four leafy vegetables (Basella alba. Hibiscus sabdariffa. Solanum macrocarpon and Lagenaria siceraria) selected and collected from two markets (Texaco and Thomas Sankara) and two market gardening sites (Jardins Talangaï and Nkombo) in the northern part of the city of Brazzaville, in Congo. The water content and pH of the selected leafy vegetables in the four sites were determined from the fresh material, while their protein, lipid, ash and mineral contents were established from the dry material using standard methods. The results reveal that the studied leafy vegetables have a very high-water content ranging from 84.49±0.36-94.63±0.68%, a pH ranging from 2.7±0.6 to 7.3±0.6, a lipid content ranging from 2.09±0.74 to 5.02±0.42%, a protein content within the range of 14.87±0.81% and 35.81±1.85%, and an ash content varying between 6.86±0.53 and 41.59±1.62%. Furthermore, these results show a high content of mineral elements, with values ranging from 3.94±0.95 to 83.57±3.7mg/100g, 920.01±0.45 to 4677.99±2.24mg/100, 101.25±1.02 to 372.80±1.56mg/100g, and 192.28±1.73 to 1452.57±4.71 mg/100g, respectively for iron, calcium, phosphorus and magnesium. In accordance to these results the studied leafy vegetables available and accessible, are rich sources of protein and micronutrients. Thus, their consumption in sufficient quantities could contribute to the improvement of nutritional status and an adequate protection against malnutrition-related diseases.