Aligned carbon nanotubes are a technologically relevant member of the family of novel carbon materials, which find applications, e.g., as field emitters in flat panel displays. Different strategies of various complexities for their production have been demonstrated. Here we present an efficient and versatile but simple method for the production of large arrays of aligned carbon nanotubes based on thermal chemical vapor deposition from common precursor molecules. Iron catalyst particles are obtained from thermal decomposition of Fe(CO)5, while C2H2 serves as carbon feedstock. Growth of aligned nanotubes is achieved under both co-deposition and deposition in separate steps of the carbonyl and acetylene.