Absorbance of extracted oil during oilseeds extrusion is important to produce high quality product. To date there is little information about fat absorption capacity (FAC) of common feedstuffs as absorbents in the extrusion process of oilseeds. The objective of current study was to determine the FAC of alfalfa hay harvested at three stages of maturity (SM; early bud, late bud and early flower) and with different particle sizes (2, 0.75 and 0.2 mm) and some feedstuffs as absorbent materials during oilseeds extrusion. In a completely randomized design, the FAC of experimental feedstuffs was different (P<0.05), and alfalfa hay had highest FAC among all absorbents (P<0.05). The FAC of alfalfa hay was not affected when particle sizes and oil sources changed (P>0.05). With advancing the SM of alfalfa hay, the FAC increased (P<0.05). Different combination of alfalfa hay and pistachio by-products had different FAC, and with an increase in the alfalfa hay portion, FAC increased (P<0.05). In conclusion, the FAC of alfalfa hay changed with advancing SM but not by different particle sizes or oil sources and different feedstuffs had various FAC.