The impact of biotechnologies on peoples' everyday lives continuously increases. Measuring young peoples' attitudes toward biotechnologies is therefore very important and its results are useful not only for science curriculum developers and policy makers, but also for producers and distributors of genetically modified products. Despite of substantial number of instruments which focused on measuring student attitudes toward biotechnology, a majority of them were not rigorously validated. This study deals with the development and validation of an attitude questionnaire toward biotechnology. Detailed information on development and validation process of the instrument is provided. Data gathered from 326 university students provided evidence for the validity and reliability of the new instrument which consists of 28 attitude items on a five point likert type scale. It is believed that the instrument will serve as a valuable tool for both instructors and researchers in science education to assess students' biotechnology attitudes.