This article presents the results of a study on the behavior of the compressive strength of a reference concrete formulated by the Dreux-Gorisse method, varying the dosage of water and cement by +/-10%, +/-20%, and +/-30%. The strength obtained for the reference concrete was 13.04MPa. However, an excessive change in the water dosage resulted in strengths of 8.438MPa, 7.05MPa, and 4.73MPa respectively for the dosages of +10%, +20%, and +30%. A deficient change in water dosage produced strengths of 14.418MPa, 15.465MPa, and 17.11MPa for the dosages of -10%, -20%, and -30%. For an excessive change in cement dosage, the strengths were 13.496MPa, 15.936MPa, and 21.575MPa respectively for the dosages of +10%, +20%, and +30%. A deficient change in the cement dosage showed strengths of 6.271MPa, 5.26MPa, and 3.207MPa for the dosages of -10%, -20%, and -30%. These results demonstrate that variations in these two components significantly affect the compressive strength of concrete. However, the change in cement dosage has a far greater impact on compressive strength than that of water.