Pt and Nafion are materials widely used in electrochemical devices including PEM fuel cells, flow batteries, electrolyzers, and electrochemical sensors. In PEM fuel cells, the catalyst layer consists of multiple materials including catalyst Platinum (Pt) or Pt-based alloys, carbon, and ionomer (usually Nafion). Laser induced breakdown spectroscopy (LIBS) is a promising analytical tool for probing the elemental composition in a sample, offering advantages of fast, in-situ, and online analysis, minimal sample preparation requirement, and the capability of spontaneous multi-element analysis. In this paper, we present a study of probing the Pt and Nafion loadings in their mixtures with graphite carbon, respectively, using LIBS technology. Pt-carbon and Nafion-carbon samples of various material loading are prepared for the LIBS testing. Plasma plume and shadowgraphic images are presented to show plasma and associated shockwave evolution. It takes a few milliseconds for spectrum collection per laser shot. Each sample analysis contains 49 shots in the present study and takes less than 1 minute. The results show LIBS is capable of probing the Pt and Nafion loadings in the mixtures. The method is useful in rapid analysis of catalyst layer composition and examination of material loss due to degradation. (c) 2017 The Electrochemical Society. All rights reserved.