The present study is based on a transformational account of verb-based nominalizations that precede the suffixes -er, -or, -ee. The theoretical foundations of this study are rooted in systemic functional linguistics and generative semantics. The aim of the research is to investigate the functional potential of -er, -or, -ee nominalizations in English. This is an attempt to reveal what semantic functions the mentioned nominalizations may perform. To achieve the aim, the collected examples were analyzed by employing descriptive, transformational and descriptive statistics methods. The semantic level plays a crucial role in determining the semantic functions of the nominalizations. In its own turn the semantic potential of the nominalizations is determined by the semantic properties of the underlying verb.