The aim of this work is to evaluate the current situation of the flora and forage production in Pyrenean hay meadows, included in the Natural Habitat Types of Community Interest (NHTCI). 104 phytosociological relevés have been recorded at 4 Huesca Pyrenean valleys, located between 900 and 1700 m a.s.l. Species appearance (percentage of biological forms and Ellenberg values) and structural variables (agronomical families, height grass and production) were measured. Also, specific richness, Shannon and Evenness indices were calculated. A total of 183 species from 34 families were founded. Presence/absence data were analysed with TWINSPAN. As a result, nine grassland groups were identified. Four alliances, Arrhenatherion elatioris, Triseto-Polygonion bistortae, Bromion erecti and Cynosurion cristati, were recognized. The three firsts are included in the NHTCI. In addition, environmental variables were compared with ANOVA test. The results show significant differences between the groups obtained by TWINSPAN for most of the variables. These sustainably managed grasslands have acceptable average productions (ca. 4300 kg DM/ha/year) and keep remarkable species richness values (33 species/plot) and Shannon diversity index (H' = 2.55).