This research was intended to investigate (test) the knowledge of the students of master degree in Elementary Education from the Faculty of Teacher Training Lugo about their knowledge on first aid and C.P.R, before and after receiving a theoretical day training practice of three hours in three different ways (First(1)-exhibition-demonstration, Second(2)- solving a practical situation of the problem in small groups and third(3)- solving a practical situation of the problem with a large group). The sample (N = 23) consisted of 9 men (39.1%) and 14 women (60.9%) studying the degree of P.E. To find out the previous knowledge about the topic and at the end of the training session we created a test that was giving to them previous the training First test(FT) and after training day Second test(ST) to see the progress of the students after the training , a questionnaire with 25 items Ad Hoc was given. The descriptive results of the FC revealed a lack of knowledge of future teachers in the P.E topic of first aid.  These procedures have been identified to make an improvement of the new teachers with appropriated training sessions. In data obtained from the ST, we reach on average more than a 90% of correct answers proving the efficacy of the methodology and duration of training given in short period of time. The retention of knowledge about this topic was shown as a limitation of the study and will be evaluated later on. In conclusion, the importance of the knowledge on the topic first aid and C.P.R in future teachers of P.E is proved after doing the test and is proposed as part of the topics to be teach on the degree.