Cesium-137 (Cs-137) accumulation by mushrooms and trees was evaluated based on the aggregated transfer factor (T (ag)) value at one and a half years after the Fukushima Daiichi Nuclear Power Plant accident. Our results suggest that (1) some genera of fungi tend to accumulate more Cs-137 than others, (2) not only Cs-137 concentration of the substrates but also its availability for fungi is an important factor determining the Cs-137 concentration in mushrooms and (3) ectomycorrhizal fungi do not necessarily enhance Cs-137 uptake by host plants when compared to arbuscular mycorrhizal fungi.