The fluorescence resonance energy transfer from fluorescein to merocyanine 540 in aqueous sodium dodecyl sulfate, cetyltrimethylammonium bromide and Triton X-100 micellar solutions as well as deionized water was investigated at room temperature using steady-state and time-resolved fluorescence spectroscopy techniques. Fluorescence resonance energy transfer rate constants (k(T)), obtained using both Stern-Volmer and Forster theories, were in good agreement. Moreover, energy transfer efficiency values of 0.14, 0.38, 0.77 and 0.85 for deionized water, sodium dodecyl sulfate, TX-100 and cetyltrimethylammonium bromide micellar solution were obtained at the highest acceptor concentration at which fluorescence resonance energy transfer was achieved. The data obtained from steady-state absorption, fluorescence spectral studies and time-resolved lifetime measurements indicated that the fluorescence resonance energy transfer from fluorescein to merocyanine 540 occurred most effectively in aqueous cetyltrimethylammonium bromide micellar solutions. (C) 2008 Elsevier Ltd. All rights reserved.