This study examined the effects of training using the slime on the hand function and problem behavior in adults with intellectual disabilities. Methods: Five adults with intellectual disabilities who were judged as Level 1 or Level 2 were selected. The training consisted of one session (50 min)/day, one day/week for 10 weeks (preparatory activities: 5 min, slime activities: 40 min, finishing activities: 5 min) The functions of the hand (Purdue Pegboard Test [PPT], grip strength test [GST]) and problem behavior (Korean Behavior Problems Inventory [K-BPI]) were assessed three times (first assessment; pre, second assessment; post-5 weeks, third assessment; post-10 weeks). Wilcoxon signed-rank tests were used to analyze changes in the subjects' performance before and after the intervention. Results: In the PPT, the use of the non-dominant hand was increased significantly (p< 0.05). No significant differences were observed in the remaining results, but the mean value increased. In addition, although the problem behavior was not statistically significant, an increase in the problem behavior score was noted. Conclusion: The training using the slime for adults with intellectual disabilities is effective in hand function improvement and reducing problem behavior.