The aim of the study was to determine the influence of different cutting dates on Cornell Net Carbohydrate and Protein System (CNCPS) parameters and the fatty acid (FM) compositons of caramba hay (Lolium multifforum cv caramba). The samples were taken from the five randomized plots at the three different cuts (first cut:before blossom, second cut:blossom 50%, and third cut:after blossom). The samples were analyzed including the crude protein (CP), ether extract (EE), CP fractions (A = NPN, B-1 fast, B-2 = intermediate, B-3 = slow and C= not fermented and available for the animal), degradable intake protein (DIP), undegradable intake protein (UIP) and the FAs compositions (C14:0, C16:0, C18:0, C18:1, C18:2 and C18:3). The CP, EE and A(1) fraction were negatively affected by the different cutting dates (P<0.05), while the B-2, B3 and C fractions were increased by growing stage (P<0.05). Different cutting dates affected total major FAs, and decreased the concentration of C18:3 (P<0.05) and increased those C16:0 (P<0.05) and C18:2 (P>0.05). A positive strong linear relation was found between the C18:3 and CP contents in caramba hay (R-2 = 0.769, P<0.001). The study showed that CP, soluble protein (A+B-1 fraction) and C18:3 were significantly decreased, the other crude protein fractions (B-2, B-3 and C) and other major FAs (C16:0 and C18:2) were increased by growing stage.