The relationship between attention and memory has been studied for a long time. Usually, dual-tasks at the memory encoding stage decrease recall performance for the studied information and impair concurrent task performance. Yet, which cognitive mechanisms are underlying this dual-task interference is still an unresolved question. Hence, we investigated the influence of a concurrent task on the encoding process of auditory information. Participants were asked to perform an auditory-verbal free recall memory task and a visual-manual spatial Stroop task in single or dual-task conditions at the encoding stage of the memory task. The temporal overlap of the stimulus presentation of both tasks was varied (i.e., different stimulus-onset asynchrony). Further, a possible relationship between memory encoding processes and response selection processes in trials with a processing conflict (i.e., incongruent trials) in the concurrent task was analyzed on a trial-level. Results showed detrimental effects on memory accuracy and concurrent task performance in the dual-task condition compared to the single-task condition. Effects of varying temporal overlap and the influence of processing conflicts in the concurrent task on memory encoding processes are further discussed.