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Dual purpose production systems (DP) in Mexico in general is characterized by beef and milk production under extensive management conditions. However they are quite diverse in terms of location, farmer socioeconomic characteristics, management, scale, production orientation, performance, and how they use natural resources. The aim of this study was to assess the effects of DP farms according to their productive orientation (PO) on vegetal diversity indices (Margalef and Menhinick) and, species richness (Shanon-Weinner and Simpson), of rangelands in Zacazonapan Municipality, southwest of the State of Mexico, Mexico. From previous studies using multivariate analysis, four groups of DP farms were identified according to their PO: i) milk production oriented (DPM); ii) beef production (DPB); iii) calf production (DPC) and, i) traditional DP (DPT). During 2010, three farms from each group were visited in order to conduct ten transects (50 x 2 m), with the objective of determining diversity and richness indices. In general, a farm´s rangelands are comprised of grazing areas with native and introduced grasses, crop areas, other herbaceous areas, brush and dispersed tropical trees. DPMs had the highest score (3.95) in Margalef index, whereas DPT had the lowest score (3.63). Regarding the Menhinick index, DPC had 1.68 (highest) while DPT scored the lowest with 1.11. DPM registered the lowest score (3.00) in Shanon-Weinner index; and DPC scored the highest (3.53). Finally, the Simpson index ranged between 0.72 (DPB) to 0.87 DPC. In general DP farms with different productive orientations showed high values in the two diversity indices, as well as the two richness indices evaluated, indicating the environmental sustainability of DP farms in the study region.