Background: Current standard of care first line treatment for extensive stage SCLC includes combination of platinum-etoposide doublet with an immune checkpoint inhibitor. Carboplatin is preferred over cisplatin in the extensive stage disease because of its favorable toxicity profile. Data comparing the efficacy of carboplatin with cisplatin in the metastatic setting are limited. Methods: Data from the National VA Cancer Cube database were compiled. Only pathologically confirmed cases of extensive stage SCLC that received platinum-based multiagent chemotherapy were included. Interval-censored Weibull and Cox proportional hazard regression models were used to estimate median overall survival (OS) and hazard ratio (HR), respectively. Two survival curves were compared by a Wald test. Results: Overall, 2600 SCLC cases were studied: 1968 received carboplatin-based therapy (Carbo-SCLC) while 632 received cisplatin-based therapy (Cis-SCLC). Median OS of Carbo-SCLC and Cis-SCLC was 0.71 years (95% CI 0.68-0.75) versus 0.70 years (95% CI 0.64-0.76), respectively (HR = 0.99; 95% CI 0.90-1.10; p = 0.90). Median OS of patients with ECOG-PS of 0, 1, 2 and 3 was similar for Carbo-SCLC and Cis-SCLC. HR of death for Carbo-SCLC compared to Cis-SCLC stratified by performance status were: ECOG-PS 0: 1.04 (95% CI 0.78-1.38; p = 0.80); ECOG-PS 1: 0.87 (95% CI 0.71-1.06; p = 0.17); ECOG-PS 2: 0.92 (95% CI 0.69-1.24; p = 0.6); ECOG- PS 3: 1.13 (95% CI 0.66-1.92; p = 0.66). Multivariable regression analysis accounting for age and ECOG-PS shows a HR of 0.92 (95% CI 0.80-1.05; p = 0.24). Conclusions: Cisplatin-based chemotherapy was not associated with a survival advantage over carboplatin-based chemotherapy in extensive-stage SCLC., including in patients with robust performance status and young patients. The findings from this large dataset along with the favorable toxicity profile of carboplatin support its use as the platinum agent of choice in extensive stage SCLC.