The assembly kinetics of a membrane protein, the bc(1) complex, was investigated using a newly developed continuous-angle laser light scattering technique. The apparent molecular weight, the radius of gyration, and the fractal dimension of aggregates in the aqueous solutions were calculated by simultaneously measuring the angular dependence on the scattering intensity with a time resolution of 1 s. It was found that the assembly of the bc(1) complex proceeded via increases in both the size and packing of the internal structure of the aggregates. This feature was qualitatively the same irrespective of whether zinc was present in the solutions. However, the fractal dimension in the final stage of assembly clearly showed a difference depending on the presence or absence of zinc in the solutions. The observed difference was consistent with the appearance of amorphous or crystalline phases. The assembly rate was controlled by the presence of zinc as well as by the concentration of PEG, the crystallizing reagent. Finally, the observed data were compared to those observed in the aggregation process of inorganic biological molecules, calcium phosphate.