Purpose: This paper's objective is to test the main effect of negotiation training-level on acquiring negotiation skills. Training level refers to the time a trainee spends in a negotiation training course receiving the standard style and methods of training. Negotiation skills are manifested through trainees' performance after receiving training. Design/methodology/approach: Six meta-analyses were conducted over 57 lab experiments from 36 studies. The six meta-analyses were divided into two groups each with a sub-study. The objective of study one is finding effect of training level on negotiators' individual and joint performance. The objective of study two is contrasting the effects of three training levels on negotiators' performance. Findings: Study one results show that training level has an effect on individual performance that is more evident for the long training (r=0.76) than for the short training (r=0.22). Training level has a medium effect on joint performance (r=0.37). Results of study two show an increase in negotiators' performance the higher the training level. That performance rate ranged from point estimate=2.03 after spending a day in training to point estimate=5.2 after spending three weeks or more in training. Research limitation/implications: The results indicate significant association between the time trainees spend in negotiation training programs and their negotiation performance. Level of training should be controlled for when conducting experiments during negotiation courses. Future research should focus on effects of personality traits of both trainees and trainers on negotiation training effectiveness. Practical implications: The findings highlight the importance of investing in increasing the level of negotiation training and spending more in making it a routine practice for top executives. After all, skilful negotiators are important assets that should be maintained. They make important deals that add to the firm's financial performance of the firm. Higher levels of negotiation training deliver more values to firms. Originality/value: Training methods and styles followed in courses and programs of negotiation training are effective and are of value providing they last for enough time. The study highlights the importance of negotiation training, an area worthy of more research. Findings are valuable for training practitioners to pay attention to what is considered enough time of training against what is being practiced. Training can be effective in building soft skills and experience in other managerial fields if designed in the appropriate way. (Contains 1 table and 3 notes.)