The author discusses approaches to studying changes occurring in normal developmental crises. A study was conducted to test the hypothesis that there is a link between the structure of ego-identity and personality changes which take place in the following normal developmental crises: transition to adulthood, the crises of 30 and 40 years of age. The paper describes a method for diagnosing ego-identity, presents findings of the experimental study of developmental characteristics of the structure of ego-identity, revealing the main new formations appearing in the process of normal developmental crises.