This paper discusses the interaction between two identical micro-slot diffusion flames. First, it is experimentally found that the burner pitch (distance between burners) influences the flame shapes and the total heat release rate. The total heat release rate, measured by integrating the intensity of CH chemiluminescence, tends to increase with a decrease in burner pitch, but it has a local minimum. The critical burner pitch at which two flames touch each other is identified as a representative parameter that characterizes the flame interaction. Then, a simple analytical model is developed to predict the critical burner pitch and the total heat release rate. A merit of the present simple model is its extensibility to other multiple-burner configurations owing to the linearity of basic equation. The predicted critical burner pitch and total heat release rate agree reasonably well with experimental data. It is thus confirmed that the proposed model can be used to predict flame interaction behaviors. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.