AADC deficiency, a rare neurometabolic disorder associated with significant developmental delay and functional impairments, requires intensive highly specialized lifelong care. This study aimed to estimate the economic burden and indirect costs of AADC deficiency from the caregiver’s perspective. An Excel model was developed to assess weekly and annual costs associated with caregiving in four European countries (Belgium, Italy, Spain, and UK). Time spent providing care, paid and unpaid support, and impact on employment were obtained via questionnaire, and country-specific associated costs, estimated using public national sources. Estimated number of individuals with AADC deficiency ranged from 2 (Spain) to 16 (Italy). Primary caregivers reported spending an average of 90 hours (range: 56-140) weekly on practical and emotional care, plus 15 hours (range: 7-33) on administrative tasks. Annually, 9,360 - 74,880 hours on average were spent on practical and emotional care, representing an estimated total of €111,852 to €1.6 million. Caregivers further spent 30 to 240 hours weekly on average (1,560 – 12,480 hours/year) on administrative tasks, representing an estimated total of €358 – €5,112 per week (€18,642 – €265,824 annually). 55% of caregivers received 35 to 277 hours weekly in paid and unpaid support (1,798 - 14,380 hours/year), translating into an estimated total of € 493 - €5,866 weekly (€25,625 to €305,006 annually). For countries studied, the resulting total cost of caregiving ranged from €5,206 - €24,018 weekly (€156,119 to €2.2 million per annum). Further, the loss of income owing to 75% of primary caregivers leaving work or reducing working hours was estimated to €16,658 - €227,429 per year. Findings show how the significant time and support needed to care for individuals with AADC deficiency and primary caregivers’ reduced participation in the workforce translate into substantial costs to society, thereby providing a further aspect of the economic burden associated with AADC deficiency.