An essential aspect of studies on fruit growth is the accurate and nondestructive on-field estimation of key variables of interest such as fresh or dry fruit weight. Allometric relationships between a key variable of interest and one or several easy-to-measure variables that are used as predictors are convenient and powerful tools for this goal. However, these relationships could be affected by different factors. Allometric relationships were built to assess fresh and dry fruit weight of 'Kenbt' mango, and the effects of growing conditions on these relationships were investigated. Length (L), orthogonal diameters (D1, D2), fresh and dry weights were recorded on individual fruits sampled at three dates during fruit growth in six orchards, one irrigated orchard on Réunion island and five irrigated and non-irrigated orchards in Senegal. Allometric relationships were estimated between fresh and dry fruit weights and the product LD1D2. The relationship between fresh fruit weight and LD1D2 was linear and unaffected by the growing conditions. The relationship between dry fruit weight and LD1D2 was allometric, i.e. followed a power function. It was then linearized by log-transformation of the two variables. The growing conditions did not affect the slope of this relationship, but affected the y-intercept. The y-intercepts estimated for each orchard were significantly correlated with the fruit dry matter content, which was also affected by the growing conditions. These results are discussed with regard to the significance of the studied relationships, and to the limits of the allometric method to estimate fruit weight.