Malnutrition and diarrheal foodborne diseases that affect children at weaning age are public health problems in developing countries. The objective of this study was to formulate a nutritious complementary food (CF) from available local products and investigate the potential of watermelon juice as alternative to contaminated cooking water as a means of preventing diarrhea and associated malnutrition. Three CF were cooked as follows: the first (CF1) "control" with water, the second (CF2) with "Kaolack" watermelon juice and the third (CF3) with "Koloss" watermelon juice. Carbohydrate content was increased (81.20 ± 0.81g/100g and 75.81 ±1.54 g /100g dry weight), respectively in CF2 and CF3 samples compared with CF1 (46.23 ± 1.30 g /100g dw). The fat level of CF1 (13.44 ± 0.94 g/100g dw) was higher than CF2 (9.53 ± 0.27g/100g dw) and CF3 (7.54 ± 0.36 g/100g dw). The protein levels of CF1, CF2 and CF3 were respectively 34.51 ± 1.30 g/100g dw, 30.08 ±0.54 g/100g dw, 26.83 ± 0.20 g/100g dw. L-citrulline contents were increased in CF2 (209.54 ± 0.21 mg/100g dw) and CF3 (212.43 ± 1.14 mg/100g dw) when compared to CF1 (39.35± 0.15 mg/100g dw) sample. All protein contents were sufficient and above the recommended value of 1.7 g/100 kcal (WHO/FAO/UNU (2002). Energy content met expectations, with CF2 (530.89 ± 7.83 Kacl/100g) and CF3 (478.42 ± 10.2 Kacl/100g) energy contents were higher than CF1 (443.92 ± 18.86 Kacl/100g) and could help reach the WHO energy recommended daily allowance for weaning food. CF2 and CF3 contained more calcium, magnesium, phosphorus, potassium and iron than CF1. Calcium, magnesium and iron contents were far above recommended levels. Also, this study showed that it is possible to have concomitantly adequate energy density and a thin complementary food viscosity when it is cooked exclusively with watermelon juice.