Computer terminology has recently become very influential in languages other than English. One of the major problems affecting Spanish translation in this field derives from the high flexibility of English towards conversion, the process whereby a term belonging to a specific grammatical category can be used with different syntactic functions without requiring change in its form. Although no agreement exists on the definition and extent of conversion, this process poses some important problems for the Spanish translation. This paper intends to analyze and classify the most important types of conversion in English computer terminology and describe the major problems affecting the Spanish translation.