U.S. and Canada have long-term monitoring programs for metals which provide important information about the status of contaminants in the Great Lakes. However, some technology-critical elements (Ce, Gd, Hf, Ir, Os, Re, Ru, Ta, W, Y) that are increasingly extracted and used in electronics have not been included in such programs to understand their presence in aquatic ecosystems. We studied the concentrations of these elements in muscle of six fish species collected from Lakes Erie and Ontario, as well as their relationships to body size and condition to understand whether biological factors affect their bioaccumulation. The highest concentrations detected were for Ce in the muscle of trout-perch (Percopsis omiscomaycus) from Lake Erie, and in the muscle of round goby (Neogobius melanostomus) from Lake Ontario. There were negative relationships for W and Y with length in S. namaycush and deepwater sculpin (Myoxocephalus thompsonii), respectively. Also, there was a negative relationship for Gd with weight in M. thompsonii. The regressions showed that Ta showed positive relationship with both length and weight of yellow perch (Perca flavescens) from Lake Erie, whereas this element showed a negative correlation (P < 0.05) with the Fulton factor in S. namaycush from Lake Ontario. These first results suggest that technology-critical elements vary within and among species from two of the Great Lakes, with some decreasing with increasing fish size, and that these data could serve as baseline information to assess trends in fish populations in these systems.