It is recommended that students are engaged at least 50% of their Physical Education (PE) classes in moderate to vigorous physical activity (MVPA). Thus, the objective was to identify the physical activity (PA) level, professor's behavior and effective time of PE classes in a public school in Chile. Through two months, 14 PE classes and three leachers were observed. Observed students were between 6 and 10 years old. Only the classes that lasted 90 minutes and were not run in extreme conditions like rain, intense heat or environmental contamination were analyzed. We evaluated 1) student's PA in percentage of time 2) class contents 3) teacher's participation. Everything was assessed through the system of observation of the time of instruction of the physical condition. The time dedicated to MVPA was 32% or the class. 68% was destined to the free practice. 90.6% the teacher did not promote the effort. The results indicate that the PA was significantly lower than the recommendation and in majority of time the PE teacher did not promote the students' effort.