The aim of this study is to find out effects of speech intelligibility on visual short-term memory performance by testing 34 interior architecture students in three different sound environments. Those sound environments were composed of real office sounds and a speech sample that are mixed to achieve varying STI levels of 'continuous noise', 'masked speech' and 'speech' sound environments [2]. Test procedure had three steps: first questionnaire, computer based short-term memory test and second questionnaire. Results show that there is no significant difference of visual short-term memory performance between varying sound environments, however subjective results derived from questionnaires show that students were distracted most by 'speech' sound environment.