The linear viscoelastic properties of a poly(styrene)-poly(ethylene, butylene) triblock copolymer in the presence of a hydrocarbon oil have been investigated. The samples were followed rheologically, during annealing at different temperatures. In a relatively small temperature interval, tan delta-curves, recorded at different frequencies, evolved in a pattern which is typical for a physical gelation. It allowed determination of the gel time. The kinetics of gel formation were found to be affected by the annealing temperature, and the rate was maximum at an intermediate temperature that depended on the polymer content of the sample. Increasing the polymer content shifted this maximum to higher temperatures. At lower temperatures, a glass transition of the polystyrene end-blocks was detected. The microphase separation temperature however, could not be determined. In addition, the influence of strain and the applicability of time-temperature superposition was analysed.