The fluorescence dynamics of protoporphyrin IX (PPIX) and protoporphyrin IX dimethyl ester (PPDME) and their zinc complexes in anionic (SDS), cationic (CTAB), and neutral (Triton X-100) micelles have been studied by picosecond time-resolved fluorescence and anisotropy decay measurements using a time-correlated single photon counting technique. The absorption and fluorescence emission spectra of the porphyrins (0.5-1 mu M) in the micelles (0.5-1 mM) are typical of the monomeric porphyrin. The absence of aggregation and homogeneity of the solubilization sites are confirmed by the fluorescence decay which is a single exponential for all the four porphyrins in the neutral and cationic micelles, Triton X-100 and CTAB. However, the presence of small. concentrations of aggregates resulted in biexponential fluorescence decay in the anionic SDS micelles. The fluorescence anisotropy decay of the monomer-micelle systems is best fitted to a two-exponential function. The values of the rotational decay parameters are consistent with the model that the fluorescence depolarization occurs by both rotational and translational diffusion of the porphyrin inside the micelle and the tumbling of the micelle. The order parameter for the porphyrin intercalation and rotational and translational diffusion coefficients have been calculated. The model is consistent with the NMR results which show that the equilibrium distribution of porphyrin is confined to a region near the surface.