This paper presents new experimental results about the sensitivity of an SRAM-based FPGA under neutron-induced and total ionizing dose effects. Both effects are combined in a practical experiment composed of a set of eight isotropic emission material blocks for neutron irradiation and a gamma rays source for ionizing dose. The experiment was performed at Instituto de Estudos Avançados, São José dos Campos, Brazil. The soft error rate has been measured from counting the bit-flip rate of the configuration memory bits and the errors at the output of the design application. Current results have shown that the soft error rate increases under neutrons when the accumulation of ionizing radiation in the device also increases until the observed doses. © 2014 IEEE.