The aim of this study is to validate an instrument to evaluate the teaching of mathematics through mathematical processes using a structural equation model. To that end, we have administered the instrument to 95 in-service Spanish teachers and we have also analysed the presence of mathematical processes (problem solving, reasoning and proof, communication, connections and representation) in teaching practice. The descriptive statistics obtained through a quantitative study show that all the items perform similarly in each of the processes, obtaining medium to high scores. A change in this trend is only detected in some of the items of the mathematical process "connections", which measure if mathematical knowledge is related to other disciplines. The results obtained from the exploratory factor analysis show a high coefficient for all the processes (higher than 0.72), as well as a significant p value, and the results obtained from the confirmatory factor analysis show an internal consistency of the items of each construct, with values greater than 0.8.