Milk is a staple food consumed by billions of people worldwide. In Algeria, milk is particularly valued not only for its nutritional benefits but also because it is heavily subsidized, making it an affordable source of protein. However, various forms of adulteration often compromise the quality of milk. In this way, this study investigates the physico-chemical quality and adulteration practices in raw cow's milk in Algeria. The analyses concerned milk arrival temperature (AT°), pH, titratable acid (TA), specific gravity (Sp.g), fat, total solids (TS), solids-non-fat (SNF), water, starch and betalactam adulteration. The results show an increased and large variability of AT° (13.84 °C ± 5.41). All samples had a pH lower than the normal pH of fresh milk with a mean of 6.44 ± 0.072, despite a normal acidity (16.64 °D ± 0.712). A mean specific gravity (Sp.g) and a mean fat content (1.0288 g/mL ± 0. 0011 and 32.24 g/L ± 1.72 respectively), far from Algerian norms; combined with the high level of milk adulterated by water (40%), an acceptable content of SNF (8.51% ± 0.269) with a weakness in TS (11.74% ± 0.318). No sample was found to be adulterated with starch. Using the Beta Star test, betalactam residues were found in 22.22% of the samples.