Thus far, few research studies have examined the practice of integrated speaking test tasks in the field of second/foreign language oral assessment. This dissertation utilized structural equation modeling (SEM) and qualitative techniques to explore the relationships among topical knowledge, anxiety, and integrated speaking test performance and to compare the influence of topical knowledge and anxiety, respectively, on independent speaking test performance and integrated speaking test performance. Three instruments were employed in this study. First, three integrated tasks were derived from TOEFL-iBT preparation materials, and three independent tasks were developed specifically for this research study. Second, four topical knowledge tests (TKTs) were constructed by six content experts and validated on a group of 421 Taiwanese EFL learners. Third, the state anxiety inventory (SAI) from the State-Trait Anxiety Inventory was adopted. A total of 352 Taiwanese EFL students were recruited for the official study. At the first stage, they filled out the personal information sheet and responded to the TKTs. At the second stage, they took two independent tasks for which they spoke without input support, responded to an SAI, performed two integrated tasks in which they orally summarized the textual and auditory input given to them, and completed another SAI. Finally, 23 volunteers took part in follow-up interviews. The quantitative data were analyzed using the two-step SEM approach and the interview data were examined using a series of qualitative techniques, leading to five primary findings. First, topical knowledge and anxiety both strongly influenced the integrated speaking performance, though in an opposite manner. Second, topical knowledge did not significantly affect anxiety. Third, the effect of topical knowledge on independent speaking performance and integrated speaking performance varied depending on the topics of the tasks. Fourth, the impact of anxiety on independent speaking performance and integrated speaking performance also differed according to the topics of the tasks. Fifth, participants were overwhelmingly positive about the integrated tasks. In light of the findings, several implications are proposed for second/foreign language oral assessment theory, research methodology, and practice. / text