Introduction: In-service training is one of the types of training that organizations provide for the development of themselves and their employees. Since adults are trained in these programs, it is necessary to consider the principles of adult education in planning the educational process; Therefore, this study was conducted to evaluate the principles of adult learning in the implementation of in-service training programs and the effectiveness of these programs from the perspective of pre-hospital emergency staff in Bam and Jiroft Universities of Medical Sciences in 2018. Methods: This research is a descriptive-analytical cross-sectional study that was performed on 167 employees of the Center for Management and Medical Accidents and Emergencies of Bam and Jiroft in 2018. The data collection tool was a three-part questionnaire including the first part of demographic information, the second part of the questionnaire on the observance of adult learning principles in inservice training and the third part of the questionnaire on the effectiveness of in-service training from a personnel perspective. The validity and reliability of the questionnaire have been reviewed and confirmed in several studies. Data were analyzed using SPSS software version 20. Results: Of the 167 participants in this study, 16 (9.6%) were female and 151 (90.4%) were male. In terms of degree, bachelor's degree with 86 people (51.5%) is the most and diploma degree with 7 people (4.2%) is the least. There was no significant difference between the observance of adult learning principles in terms of demographic variables and also between the effectiveness of education and demographic variables, but there was a statistically significant relationship between the observance of adult learning principles and the effectiveness of in-service education. Conclusion: Considering the significant relationship between adherence to the principles of adult learning and the effectiveness of in-service training, it is suggested that in order to increase the effectiveness of inservice training in the planning, implementation and evaluation stages, be reviewed in terms of compliance with adult learning principles.