The productivity and profitability of the use of maize silage (MS) within pasture-based beef production systems was evaluated using the Farmax Pro® model. Farm systems were simulated based on an intensive oneyear-old steer production system with two pasture growth patterns (Waikato and Hawkes Bay), three different proportions of the farm in MS production (0%, 5% or 10%) and MS fed either during winter (W) or summer (S). MS cost 13.5 and 16.1 c/kg dry matter (DM) for Waikato and Hawkes Bay respectively. This price included the cost of growing, harvesting, ensiling and feeding. Beef schedule prices were based on $1.80/kg live weight (LW). Feeding MS increased beef production in all scenarios tested by a mean of 36% with values of 427, 581 and 576 kg net meat/ha/year for the no MS, S and W feeding systems respectively. Farm profitability (gross margin per hectare) was increased by feeding MS in W and S, with values of $934 and $754 respectively, compared with the no MS system of $636. MS feeding was still profitable at a schedule price of $1.40/kg LW and at higher MS costs up to 23 c/kg DM. Appropriate use of MS in beef production systems can substantially improve animal performance and farm profitability.