Objectives: This study investigated cognitive-motor interference on the relationship of speed and accuracy during a cognitive and upper-limb motor dual task. Method: Nine stroke patients (56.5±7.3 years; M:9) participated in a series of cognitive-motor dual tasks. A subject with chronic stroke was seated with paretic hand fastened on the handle and then one of five motor tasks was provided (Figure 1A). Visual feedback in a front screen was synchronized as the handle cursor moves within the movement trajectory with two difficulty levels (5cm or 10cm). In a dual task, a cognitive task, Serial Seven(S7), was concurrently provided with a randomly chosen number at the onset of the motor task by a test administrator.Figure 1 Cognitive-Motor dual task setup (left up) and trajectory shapes (Diagonoal; Mediolateral; Anteroposterior; Cross; Circle) and level of difficulties (Easy 10cm or Hard 5cm) in motor tasks. The motor speed and accuracy and the cognitive speed and accuracy were evaluated during one-minute trial time. Pearson-correlation coefficients evaluated outcome relationship of the speed and accuracy in single or cognitive-motor dual tasks with the significance level 0.05 using a commercial statistics package (SPSS ver 22, Chicago IL,US). Results: There were significant positive correlation between single and dual motor speeds ( Easy :R 2 =0.678,p<0.001; Hard : R 2 =0.714,p<0.001) and significant negative correlationbetween single motor speed and dual cognitive speed ( Easy : R 2 =0.661,p<0.001; Hard :R 2 =0.6523,p<0.001) (Figure 1B) Conclusions: There were significant correlations between the upper-limb horizontal movements with visual feedback and S7 cognitive task. This study may provide useful information on upper-limb motor robotic therapies using 2D horizontal upper-limb movements.