Abstract. A performance assessment for ELMy H-mode operation of ITER-FEAT mainly at the nominal plasma current of 15 MA is made by using 1.5D transport codes PRETOR and ASTRA. Operation domain analysis is performed for various transport assumptions. Sensitivities to density profile, the ratio of ion thermal diffusivity to electron thermal diffusivity / and the ion heating fraction are investigated. It is shown that, under rather conservative assumptions, 400 MW operation with fusion gain Q = 10 should be achievable. Operations with lower and higher fusion power are explored and an operation range of 200 600MW is obtained. A probabilistic performance assessment is also done by using 0D modeling. The ``maximized conditional probability (MCP)'' to reach Q larger than a specified lower bound is estimated considering the beta limit 2.5, L-H transition threshold power and density limit ne/nGR 0.85. The MCP of achieving Q 10 is about 70%, and the MCP of Q 50 is about 30% when the HH factor distribution is a Gaussian with = 20%. By increasing the plasma current to 17 MA, the MCPs of achieving Q 10 and Q 50 increase to 85% and 50%, respectively.