Androgen and estrogen act not only in a sex-specific manner but also interactively and synergistically. In the present study, to examine the possible interaction between androgen receptor (AR) and estrogen receptor-α (ERa), we investigated the subcellular dynamics of AR and ERα fused with green fluorescent protein color variants in single living cells using time-lapse microscopy and the technique of fluorescence recovery after photo-bleaching. AR and ERα showed punctate colocalization in the nucleus with estrogen, but not androgen. N-terminal AR deletion mutant did not form a nuclear punctate pattern with either androgen or estrogen. In the presence of AR, but not ERα, N-terminal AR deletion mutant formed a punctate nuclear pattern with androgen. AR had different mobility depending on the ligand and the presence of ERα. On the other hand, AR had little effect on the stability of ERα. ERα mutant that does not bind coactivators did not alter the mobility of AR. Taken together, using an imaging technique, we clarified that possible homo/hetero dimerization between AR and ERα could be attributed to androgen-estrogen interaction in living cells.