The stability of broad-spectrum antibiotic meropenem was studied in order to investigate the kinetics of degradation of this drug in powder for injection and reconstituted sample. Carbapenem was submitted to conditions of accelerated thermal decomposition. Degradation of meropenem was adequately modeled by specific equations for order rate kinetics. The analyses of the degraded samples were performed by high-performance liquid chromatographic (HPLC) method and microbiological assay. At higher temperatures, the decomposition reactions of meropenem in powder for injection could be described by first-order kinetics. The higher rate of degradation was observed in meropenem reconstituted in 0.9% sodium chloride, and the thermal decomposition obeyed also first-order kinetics. The results obtained confirm the reliability of chromatographic method for determining the kinetics run of meropenem in the presence of its degradation products. The present study reveals the thermal lability of the drug, especially as reconstituted sample. Thus, appropriate thermal protection is recommended during the storage and handling.