The purpose of this study is to explore the capacity of the working memory among secondary stage students in Amman second educational directorate and its relationship with their ability to retain information. To explore their level of working memory, listening test period developed by (Daneman & Carpenter, 1980) was used, and the test consisted of 40 items. Moreover, the researcher used retention ability test in biology with 20 items. The sample of the study was selected from eight schools through random clustering total 293 male and female students in the school year 2010/2011. The findings of the study showed that the capacity of the working memory among students was high and their ability to retain was low. There is a positive significant relationship between the capacity of the working memory and the level of the ability to retain information. Based on the findings of the study, the researchers recommended the need of taking careful attention to mnemonics and the strategies that may help working memory in restoring and processing, concentrating in teaching methods that help students to employ more than one sense in addition to the direct experience in teaching to increase the working memory capacity among students and help them to improve information processing strategies. Moreover, they conduct more studies on working memory and its relationship with psychological and cognitive variables in other educational stages.