BACKGROUND: Tuberculosis (TB) care can be costly for patients and their families. The End TB Strategy includes a target that zero TB affected households should experience catastrophic costs associated with TB care. Costs are catastrophic when a patient spends 20% or more of their annual household income on their TB diagnosis and care. In Solomon Islands the costs of TB care are unknown. The aim of this study was to determine the costs of TB diagnosis and care, the types of costs and the proportion of patients with catastrophic costs. METHODS: This was a nationally representative cross-sectional survey of TB patients carried out between 2017 and 2019. Patients were recruited from health care facilities, from all ten provinces in Solomon Islands. During an interview they were asked about the costs of TB diagnosis and care. These data were analysed using descriptive statistics to describe the costs overall and the proportions of different types of costs. The proportion of patients with catastrophic costs was calculated and a multivariate logistic regression was undertaken to determine factors associated with catastrophic costs. RESULTS: One hundred and eighty-three TB patients participated in the survey. They spent a mean of 716 USD (inter quartile range: 348-1217 USD) on their TB diagnosis and care. Overall, 62.1% of costs were attributable to non-medical costs, while income loss and medical costs comprised 28.5 and 9.4%, respectively. Overall, 19.7% (n = 36) of patients used savings, borrowed money, or sold assets as a financial coping mechanism. Three patients (1.6%) had health insurance. A total of 92.3% (95% CI: 88.5-96.2) experienced catastrophic costs, using the output approach. Being in the first, second or third poorest wealth quintile was significantly associated with catastrophic costs (adjusted odds ratio: 67.3, 95% CI: 15.86-489.74%, p <  0.001). CONCLUSION: The costs of TB care are catastrophic for almost all patients in Solomon Islands. The provision of TB specific social and financial protection measures from the National TB and Leprosy Programme may be needed in the short term to ameliorate these costs. In the longer term, advancement of universal health coverage and other social and financial protection measures should be pursued.