Purpose To determine whether healthcare use and return-to-work (RTW) outcomes differ with GPs' injured-worker caseload. Methods Retrospective analyses of the Compensation Research Database, which captures approximately 85% of all injured worker claims in Victoria, Australia was conducted. Four injured-worker caseload groups were examined that represented the 25th, 50th, 75th, and 100th percentiles of claimants seen per GP over the 8-year study period (2003-2010): (i) 1-13 claimants; (ii) 14-26 claimants; (iii) 27-48 claimants; and (iv) 49+ claimants (total claims, n = 124,342; total GPs, n = 9748).The characteristics of claimants in each caseload group, as well as the influence of caseload on three outcomes relevant to RTW (weekly compensation paid, work incapacity days, medical-and-like costs), were examined. Results Distinct profiles for high versus low caseload groups emerged. High caseload GPs treated significantly more men in blue collar occupations and issued significantly more 'alternate duties' certificates. Conversely, low caseload GPs treated significantly more women in white collar occupations, predominantly for mental health injuries, and issued significantly more 'unfit-for-work' certificates. Few significant differences were found between the two intermediate GP caseload groups. High caseload was associated with significantly greater medical-and-like costs, however, no caseload group differences were detected for weekly compensation paid or duration of time-off-work. Conclusions Training GPs who have a low injured-worker caseload in workers' compensation processes, utilising high caseload GPs in initiatives involving peer-to-peer support, or system changes where employers are encouraged to provide preventive or rehabilitative support in the workplace may improve RTW outcomes for injured workers.