According to two multicenter, comparative, randomized, opened-labeled studies efficacy of raltitrexed and 5-fluorouracil plus leucovorin (5-FU+LV) for advanced colorectal cancer doesn't differ significantly. 5-FU+LV in Russia is much cheaper in Russia than raltitrexed but there is a significantly higher rate of severe side effects, such as neutropenia and mucositis, that may have influenced the costs. OBJECTIVE: Economical evaluation of raltitrexed versus 5-FU+LV (regimen Machover) for treatment of advanced colorectal cancer in Russia. METHODS: Decision model was used to quantify costs of alternative treatment. Published results from two trials were used to estimate probabilities of end-points (neutropenia, mucositis or no severe side-effects). Medical costs of treatment included costs of chemotherapy, treatment for side effects (neutropenia and mucositis), hospitalization and/or visits. Costs for chemotherapy were calculated on the basis of standard recommendations; costs for neutropenia and mucositis were assessed by retrospective analysis of 60 medical charts at Moscow Hematological Center. One-way sensitivity analysis was performed. RESULTS: The medium costs on one cycle of cytostatic therapy were 20 771,00 rubles (716,2 USD) for raltitrexed and 7 407,55 rubles (255,4 USD) for 5-FU+LV. The median treatment cost for side effects has compounded 25 373,95 rubles (875,0 USD) per person with neutropenia and 52 050,85 rubles (1794,9 USD) per person with mucositis. Expected costs for treatment of colorectal cancer taking into account both side effects was 85 647,46 rubles (2953,4 USD) for raltitrexed and 67 656,95 rubles (2333,0 USD) for 5-FU+LV. Sensitivity analysis demonstrated that the expected costs of raltitrexed therapy are less than 5-FU+LV when maximum value of costs for side effects are included into the model. CONCLUSION: Raltitrexed is more safe but more expensive than 5-FU+LV, but difference in costs decreases when severe side effects are taken into account.