This paper presents the results of a study into the influence of size of the test sample on the maximum load carrying capacity of cable bolts. As part of the design for the standardisation of the laboratory pullout test, it was previously found that the size of the sample in which the cable bolt is embedded can influence the behaviour of the cable bolt in terms of the peak load carrying capacity. This testing was done with a low capacity plain strand cable bolt with the sample in an unconfined state. Confinement of the sample during testing better simulates the in situ condition of the interaction between the cable bolt and surrounding rock mass. A test program was undertaken to assess whether there was any significant difference in the load carrying capacity with varying diameter of test samples and at different levels of confinement. A series of pull-out tests were conducted on cable bolts embedded into samples varying between 150 mm and 500 mm in diameter that were placed within a steel cylinder to provide confinement to the test samples. It was found maximum load varied with the test sample diameter up to some threshold diameter but that confinement pressure also had a significant effect on the load carrying capacity of a cable bolt.