Previous research on the interaction between pairs suggests there is a positive relationship between transactive discussion and effective problem solving. Debugging is particularly problematic for novice programmers. Some previous studies suggest this difficulty may be lessened by working in pairs. Using transactive analysis, we examined interactions between five pairs of university-level introductory programming students as they debugged Java programs. Transcriptions of their verbal interactions were coded into transactive statement categories which revealed that the nature of participants' discourse varied. Extensions, feedback requests, critiques and completions were the most frequently observed types of transactions. Other transaction types were rarely detected in this context. The amount of discussion for the pairs varied as did the number of transactive statements. Results suggest that pairs who talked more and used completion transactions more often attempted more problems, but those who critiqued more frequently successfully debugged more problems. The teaching implications of this work and recommendations for future research are discussed.