The objective of this article is to analyze the ratio of cost-effectiveness and budgetary impact of lenalidomide treatment in patients with multiple myeloma who have undergone autologous transplant in Spain. The analyses were based on clinical trials CALGB 100104 and IFM 2005-02, from the perspective of the National Health System. The alternatives compared were the treatment with lenalidomide against maintenance without treatment (MwT). Efficiency measures used were years of life gained (YGs) and quality-adjusted life years (QALYs). According to the CALGB 100104 trial data, the average health costs of patients who were treated with lenalidomide for 120 months was €836,534.31 and without treatment was €528,963.63. The effectiveness of the lenalidomide group was 7.59YGs (5.72 QALY) against 6.58 of MwT (4.61 QALY). The incremental cost-utility ratio (ICUR) was €277,456.72/QALY and the incremental cost-effectiveness ratio was €303,191.05/YGs. From the analysis, the IFM2005-02 trial obtained 5.13 QALY in the lenalidomide group against the 4.98 QALY in the MwT group, with an ICUR of €1,502,780.55/QALY. In terms of budgetary impact, a range between 799 and 1452 patients susceptible to receive treatment with lenalidomide was assumed in Spain. In conclusion, the results show a high ICUR and budgetary impact, which adds uncertainty about the maximum prudent duration of the treatment.