Objectives: We evaluated how next generation sequencing (NGS) can modify care pathways in an observational impact study in France.Methods: All patients with lung cancer, colorectal cancer, or melanoma who had NGS analyses of somatic genomic alterations done in 1 of 7 biomolecular platforms certified by the French National Cancer Institute (INCa) between 2013 and 2016 were eligible. We compared patients' pathways before and after their NGS results. Endpoints consisted of the turnaround time in obtaining results, the number of patients with at least 1 genomic alteration identified, the number of actionable alterations, the impact of the genomic multidisciplinary tumor board on care pathways, the number of changes in the treatment plan, and the survival outcome up to 1 year after NGS analyses.Results: 1213 patients with a request for NGS analysis were included. NGS was performed for 1155 patients, identified at least 1 genomic alteration for 867 (75%), and provided an actionable alteration for 614 (53%). Turnaround time between analyses and results was on average 8 days (Min: 0; Max: 95) for all cancer types. Before NGS analysis, 33 of 614 patients (5%) were prescribed a targeted therapy compared with 54 of 614 patients (8%) after NGS analysis. Proposition of inclusion in clinical trials with experimental treatments increased from 5% (n = 31 of 614) before to 28% (n = 178 of 614) after NGS analysis. Patients who benefited from a genotype matched treatment after NGS analysis tended to have a better survival outcome at 1 year than patients with nonmatched treatment: 258 days (±107) compared with 234 days (±106), (P = .41).Conclusions: NGS analyses resulted in a change in patients' care pathways for 20% of patients (n = 232 of 1155).