Lung cancer is the leading cause of cancer mortality worldwide. Non-small cell lung cancer (NSCLC), accounting for about 85% of all lung cancers, includes squamous carcinoma, adenocarcinoma and undifferentiated large cell carcinoma. The majority of patients have advanced disease at diagnosis, and medical treatment is the cornerstone of management. Several randomized trials comparing third-generation platinum-based doublets concluded that all such combinations are comparable in their clinical efficacy, failing to document a difference based on histology. However, recent evidences, arising from the availability of pemetrexed, have shown that histology represents an important variable in the decision making. The major progresses in the understanding cancer biology and mechanism of oncogenesis have allowed the development of several potential molecular targets for cancer treatment such as vascular growth factor and its receptors and epidermal growth factor receptor. Targeted drugs seem to be safer or more effective in a specific histology subtype. All of these data have led to choose the optimal first-line treatment of advanced NSCLC based on histologic diagnosis. However, this scenario raises a diagnostic issue: a specific diagnosis of NSCLC histologic subtype is mandatory. This review will discuss these new evidences in the first-line treatment of advanced NSCLC and their implication in the current clinical decision-making.