Docetaxel is a well-known causative agent of nail alterations. The aim of this study was to reveal the impact of nail alterations associated with low-dose metronomic (LDM) docetaxel chemotherapy on the survival of non-small cell lung cancer (NSCLC) patients. Clinical information, survival data and nail alterations in patients treated with LDM docetaxel chemotherapy (docetaxel 15 mg/m2 per week) were retrospectively reviewed. Forty-nine patients were included in this study. Various nail alterations were observed in 17 of the 49 patients (34.7%). Onycholysis and subungual hyperkeratosis were observed in 22.4% and 10.2% of patients, respectively. The number of docetaxel administration cycles was correlated with the incidence and severity of nail alterations. Univariate and multivariate analysis clearly demonstrated that the occurrence of nail alterations was an independent favorable prognostic factor for overall survival. Nail alterations associated with treatment may act as a surrogate marker for the efficacy of low‐dose metronomic docetaxel chemotherapy.