The short-term clinical results of the CLASICC trial indicated that clinical outcomes were similar between laparoscopic and open approaches. This study presents the short-term (3 month) cost analysis undertaken on a subset of patients entered into the CLASICC trial (682 of 794 patients). As expected the costs associated with the operation were higher in the 452 patients randomised to laparoscopic surgery (lap) compared with the 230 randomised to open procedure (open), Pounds 1703 vs Pounds 1386. This was partially offset by the other hospital (nontheatre) costs, which were lower in the lap group (Pounds 2930 vs Pounds 3176). The average cost to individuals for reoperations was higher in the lap group (Pounds 762 vs Pounds 553). Overall costs were slightly higher in the lap group (Pounds 6899 vs Pounds 6631), with mean difference of Pounds 268 (95%CI -689 to 1457). Sensitivity analysis made little difference to these results. The cost of rectal surgery was higher than for colon, for lap (Pounds 8259 vs Pounds 5586) and open procedures (Pounds 7820 vs Pounds 5503). The short-term cost analysis for the CLASICC trial indicates that the costs of either laparoscopic or open procedure were similar, lap surgery costing marginally more on average than open surgery.