OBJECTIVES:  Up to 7% of patients with non-small cell lung cancer (NSCLC) have a rearrangement of the anaplastic lymphoma kinase (ALK) gene. Crizotinib has been identified as a potent ALK inhibitor and has demonstrated superior efficacy in a number of clinical studies. With its recent approval, the objective of this study was to investigate crizotinib’s real-world effectiveness among ALK+ NSCLC patients across several countries. METHODS:  A multi-country retrospective medical chart-review of NSCLC patients was conducted by cancer-treating physicians in the United States (N=7,334), 5EU (France, Germany, Italy, Spain, UK; N=16,549), and Japan (N=3,492) between Q2 2015 and Q1 2016. Physicians randomly selected patient charts currently on an anti-cancer regimen and abstracted data on patient demographics, disease status, treatment patterns, and biomarker status. Only patients who were ALK+ were included in the analyses. Treatment response between those who had used crizotinib in their prior treatment line and control patients who had used a non-crizotinib treatment in their prior treatment line was examined using a generalized ordered logit model controlling for baseline differences. RESULTS:  A total of 1,471 patients were ALK+ and were included (crizotinib: N=336 vs. controls: N=1,135). Compared with controls, patients using crizotinib were more likely to come from Germany and Spain, to be younger, and to be passive/non-smokers (all p<.05). Patients using crizotinib were also more likely to have been diagnosed in stage IIIb/IV and have a lower ECOG score (both p<.05). Controlling for baseline differences, patients using crizotinib were significantly less likely to experience recurrence/progression (odds ratio (OR) = 0.38, 95%CI: 0.24, 0.59; p<.05) and significantly more likely to experience a complete response (OR=2.65, 95%CI: 1.69, 4.15; p<.05). CONCLUSIONS:  As more ALK inhibitor treatments become available, it will be increasingly important to demonstrate the real-world effectiveness of these treatments. The results suggest a significantly better response for ALK+ patients using crizotinib.