Abstract The sampling ability of a suction sampler is analysed from the results of six samples collected at a single station at Lamberts Bay on the west coast of South Africa. The vertical distribution of the fauna to a depth of 60 cm within the sediment was investigated. A mean of 18.4% of individuals were found between a sediment depth of 30 and 60 cm. The suction sampler had a high efficiency at capturing the fauna under its surface area. However, probably not all the fauna was recorded since some would most likely have lived below a sediment depth of 60 cm. Most common and many rare species living at the station were recorded and the faunal distribution is shown to be homogeneous. Calculations are made on the effectiveness with which a stated number of samples recorded all the total and common species found in the six samples combined. Two samples are shown to give a mean effectiveness of approximately 85% of the common species. Coefficient of variation values for species and individuals are calculated and the latter values are found to be lower than given by previous workers using different sampling equipment.