The need for recycling of composite material waste drove the recent development of composite oriented strand board (COSB). During development and manufacturing of this recycled material, material characterization is critical. Thus, Lamb wave characteristics for COSB plates are investigated. Several COSB samples are made of reused carbon fiber prepreg waste using different material compositions and manufacturing techniques. A focus is placed studying the effects of chip aspect ratios on Lamb wave characteristics. Specifically, wave properties such as velocity, spectral amplitude, sideband peak count are determined for each plate. High variability in the data do not allow for determination of clear correlations between chip aspect ratios and the studied wave parameters.