Background Few charitable overseas surgical missions produce cost-effectiveness analyses of their work. Methods We compared the pre- and postoperative health status for 157 total hip arthroplasty (THA) patients operated on from 2007 to 2011 attended by an annual Canadian orthopedic mission to Ecuador to determine the quality-adjusted life years (QALYs) gained. The costs of each mission are known. The cost per surgery was divided by the average lifetime QALYs gained to estimate an incremental cost-effectiveness ratio (ICER) in Canadian dollars per QALY. Results The average lifetime QALYs (95% CI) gained were 1.46 (1.4–1.5), 2.5 (2.4–2.6), and 2.9 (2.7–3.1) for unilateral, bilateral, and staged (two THAs in different years) operations, respectively. The ICERs were $4,442 for unilateral, $2,939 for bilateral, and $4392 for staged procedures. Seventy percent of the mission budget was spent on the transport and accommodation of volunteers. Conclusion THA by a Canadian short-stay surgical team was highly cost-effective, according to criteria from the National Institute for Health and Care Excellence and the World Health Organization. We encourage other international missions to provide similar cost-effectiveness data to enable better comparison between mission types and between mission and nonmission care.