Detailed magnetization measurements are performed up to H=110 kOe in the temperature range 4.2 K<T<70 K on the ferrimagnetic normal spinel MnV/sub 2/O/sub 4/ (T/sub c/ approximately=56 K). In the (M, T) plane, all isofield curves display hysteresis loops which are located between two temperatures T/sub a/ (H/sub i/) and T/sub A/" (H/sub i/), increasing with H/sub i/. From these T/sub a/ and T'/sub a/ values, a (H, T) phase diagram is derived, delimitating five magnetic regions, which is in excellent agreement with the set of isotherm magnetization curves. It is assumed that both T/sub a/ (H) and T'/sub a/ (H) are first-order transition lines, the increased stability of the triangular configuration with H being discussed in terms of a large spin-orbit coupling of the V/sup 3+/ magnetic moments.<<ETX>>