Background: Dementia is a chronic disease that will affect the function and the dependency of patient, thus requiring assistance from the caregiver to fulfill their daily needs. Family caregivers providing care to dementia patients are influenced by knowledge. Knowledge is one of the abilities needed in caring for dementia patients. Objective: The aim of this study is to give the description about caregiver’s knowledge that treating patients with dementia. Method: This study is a descriptive quantitative study using cross sectional design. Selection of sample was done by using non probability purposive sampling technique. The sample consisted of 53 family caregivers that have been recorded in medical record of Dr. Sardjito Hospital Yogyakarta on May 2018 by using inclusion criteria i.e. 1) took care a patient with dementia, 2) aged more than 18 years old, and 3) willing to become the respondents of this study. Data were obtained by using dementia knowledge assessment scale (DKAS) questionnaire which has been translated to Indonesian language. Data were analyzed using univariate analysis. Results: Majority respondents were women and aged more than 65 years old and has been taking care the patient more than 6 months. The majority type of dementia of the patients was vascular. Their average knowledge score were 23,25 from the maximum 50 total score. The highest average score was in domain 3, i.e. care consideration (8,17 ± 2,64), and the lowest one is in domain 2, i.e. communication and behavior (4,19 ± 1,82). Conclusion: Family caregivers’ knowledge about dementia that consist of several domain were still categorized as low.Keywords: dementia; family caregiver; knowledgeABSTRAKLatar belakang: Demensia merupakan penyakit kronis yang memengaruhi fungsi kerja dan kemandirian dari pasien, sehingga dibutuhkan peran caregiver dalam perawatan dan pemenuhan kebutuhan sehari-hari. Family caregiver memberikan perawatan kepada pasien demensia dipengaruhi oleh pengetahuan. Pengetahuan merupakan salah satu kemampuan yang diperlukan dalam merawat pasien demensia. Tujuan: Mengetahui gambaran pengetahuan family caregiver dalam merawat pasien demensia. Metode: Penelitian ini merupakan penelitian deskriptif kuantitatif dengan menggunakan rancangan cross sectional. Pemilihan sampel dilakukan dengan teknik sampling nonprobability purpossive sampling. Sampel terdiri dari 53 family caregiver pasien demensia yang tercatat klinik memori RSUP Dr. Sardjito pada bulan Mei 2018 dengan kriteria inklusi, yaitu 1) family caregiver pasien demensia, 2) usia lebih dari 18 tahun, dan 3) bersedia menjadi responden penelitian. Data diperoleh dengan menggunakan kuesioner data demografi dan Dementia Knowledge Assesment Scale (DKAS) yang telah diterjemahkan ke dalam bahasa Indonesia. Analisis data menggunakan analisis univariat. Hasil: Mayoritas family caregiver rata-rata berusia lebih dari 65 tahun, perempuan, dan telah merawat pasien lebih dari 6 bulan. Jenis demensia yang paling banyak diderita pasien adalah demensia vaskular. Pengetahuan family caregiver pasien demensia rata-rata adalah 23,25 dari skor total maksimal 50. Rata-rata skor pengetahuan family caregiver tentang demensia tertinggi adalah pada domain 3 care consideration (rata-rata 8,17 ± 2,64) dan terendah pada domain 2 communication and behaviour (rata-rata 4,19 ± 1,82). Kesimpulan: Pengetahuan family caregiver tentang demensia masih dalam kategori kurang.Â