The purpose of this study was to find care need combinations for dementia patients with multiple chronic diseases and their caregivers. A cross-sectional study was conducted with 83 patients who had multiple chronic diseases. Variables from patients included age, gender, severity of clinical dementia rating, feeding, hypnotics, mobility, getting lost, mood symptoms, and behavioral and psychological symptoms. Moreover, 26 types of care needs were included in this study. The Apriori algorithm was employed to first identify care need combinations and then to find the relationships between care needs and variables from dementia patients with multiple chronic diseases. Six rules were generated for care need combinations. Four care needs could be formed as a basic care need bundle. Moreover, two additional care needs could be added to provide a wider coverage for patients. In the second stage, 93 rules were found and categorized into three groups, including 2, 6, and 28 general rules with support of 30% but less than 40%, 20% but less than 30%, and 10% but less than 20%, respectively. When the support value is 10% but less than 20%, more variables from patients were found in rules which help the dementia collaborative care team members provide tailor-made care need bundles. Four basic care needs were social resources referral and legal support (Care (1)), drug knowledge education (Care (3)), memory problem care (Care (5)), and fall prevention (Care (8)). Besides, disease knowledge education (Care (2)) and hypertension care (Care (16)) were frequent unmet needs in this specific population. Moreover, care for the mood of the caregiver (Care (11)) should be considered especially in dementia patients with preserved ambulatory function or with symptoms of hallucination. The collaborative care team should pay more attention to those care needs when assessing this specific population.