Online learning has been rapidly developing in the last decade. However, there is very little literature available about the actual adoption of online synchronous assessment approaches and any guidelines for effective assessment design and implementation. This paper aims at designing and evaluating the possibility of applying online synchronous assessments in a formal credit course. Relying on the four dimensions of knowledge taxonomy, this paper describes four different online synchronous assessments for conducting a formal mid-term exam, including synchronous quiz, synchronous practicum, synchronous essay and synchronous oral assessments. The designs were implemented and evaluated in a synchronous cyber classroom for an online credit course. This study identified the challenges and potential issues while conducting the online synchronous assessments, including (1) the extent of monitoring and cheating; (2) the lack of suitable software tools specifically for supporting online synchronous assessments; and (3) the need for a variety of online synchronous assessment methods for different subject matter. This paper concludes with some possible solutions, such as a short time limit for answering questions and a well analysed need of a software tool, to address all the issues.