Four practical approaches taken by teachers in their attempts to help students acquire the minimum sight vocabulary necessary for reading English for Science and Technology (EST) texts are described. Over a period of 12 weeks, subjects (native Spanish speakers at university level) were divided into 4 intact groups and worked under different conditions. Initial measurement showed that the groups were not significantly different and that all subjects featured low levels of vocabulary knowledge. Comparison of means obtained in a final test revealed that all groups improved their vocabulary significantly, and that the different approaches seemed to have helped to different degrees. The approach that produced the most improvement was that which trained subjects in the use of a specific vocabulary-memorizing technique. Due to the use of intact, numerically varying groups, results should be viewed with caution. However, they are consistent with previous research findings showing that Hispanic students with strategy training improved their vocabulary (O'Malley and Chamot, 1990). In addition, our results also conform to research showing that students, especially those at lower levels of proficiency, are accustomed to and favor the use of mechanical strategies for learning vocabulary (Schmitt, 1997; Riazi and Alvari, 2004).