This paper presents a study conducted at the University of Maryland to validate a suite of Object-Oriented (OO) design metrics introduced by Chidamber & Kemerer (1994). The study aims to assess these metrics as predictors of fault-prone classes. Data were collected from eight medium-sized information management systems developed using a sequential life cycle model, the Object-Oriented Analysis/Design Method (OMT), and the C++ programming language. The study found that several of Chidamber & Kemerer’s OO metrics are useful for predicting class fault-proneness during the early phases of the software development life cycle. These metrics outperform traditional code metrics, which are collected later in the development process. The paper discusses the strengths and weaknesses of the validated OO metrics and suggests future research directions, including replicating the study in an industrial setting.This paper presents a study conducted at the University of Maryland to validate a suite of Object-Oriented (OO) design metrics introduced by Chidamber & Kemerer (1994). The study aims to assess these metrics as predictors of fault-prone classes. Data were collected from eight medium-sized information management systems developed using a sequential life cycle model, the Object-Oriented Analysis/Design Method (OMT), and the C++ programming language. The study found that several of Chidamber & Kemerer’s OO metrics are useful for predicting class fault-proneness during the early phases of the software development life cycle. These metrics outperform traditional code metrics, which are collected later in the development process. The paper discusses the strengths and weaknesses of the validated OO metrics and suggests future research directions, including replicating the study in an industrial setting.