In XML Schema development, the quality of XML Schemas is a crucial issue for further steps in the life cycle of an application, closely correlated with the structure of XML Schemas and different building blocks. Current research focuses on measuring complexity of XML Schemas and mainly do not consider other quality aspects. This paper proposes a novel quality measuring approach, based on existing software engineering metrics, additionally defining quality aspect of XML Schemas in the following steps: (1) definition of six schema quality aspects, (2) adoption of 25 directly measurable XML Schema variables, (3) proposition of six composite metrics, applying 25 measured variables and (4) composite metrics validation. An experiment using 250 standard XML Schemas collected from available e-business information systems was conducted. The results illustrate influence of XML Schema characteristics on its quality and evaluate applicability of metrics in the measurement process, a useful tool for software developers while building or adopting XML Schemas.