The purpose of this study was to examine the effects of different revel of attention on implicit and explicit memory. In addition, different testing methods were examined to clarify the measurement problem of implicit and explicit memories. Two experiments were designed to create different levels of attention. A total of 110 subjects were recruited for the study. In the first experiment, attention was altered as "low" and "high attention", while implicit memory was measured by a stem-completion test and explicit memory by an old-new recognition test. In the second experiment, attention was manipulated as "divided" and "full" attention, where implicit and explicit memory was measured by both the "process dissociation method" and the methods used in Experiment 1. The most important finding was that; attention variable produced a dissociation between implicit and explicit memory. The increase or decrease of attention (or divided attention) did not affect implicit memory, whereas it negatively affected explicit memory. Attention was discussed in terms of multi-mode theory of attention and automatic-effortful distinction of attention. The findings obtained from the experiments were found supportive for both the information processing and the multiple memory systems approaches of explaining implicit memory. Process dissociation method was discussed on the basis of its assumptions and findings from the experiments. It was concluded that bath the traditional measuring methods and the process dissociation method have their own limitations and both should be used cautiously.