Patients' delay in seeking health care is a major problem in the control of tuberculosis (TB) and increases the risk of TB transmission. This study determined health-seeking practices and delays that occurred from the onset of TB symptoms until diagnosis and assessed the patients' TB-related knowledge. This was a cross-sectional study involving 391 new TB patients recruited from health facilities at an urban sub-district in South Africa from December 2016 to March 2017. Descriptive statistics and logistic regression analyses were performed using Stata 14. Over half (56.3%) of the patients delayed seeking health care for more than 30 days after the onset of their symptoms, 32% sought treatment from informal providers, and 13.3% self-medicated. Lack of suspicion of a TB diagnosis, which was prevalent in 45% of respondents, was statistically associated with delay in seeking healthcare (AOR = 0.53, CI: 0.32-1.87). Overall TB knowledge was high, correct knowledge about TB transmission was 92.6%. TB knowledge was significantly associated with educational status (AOR = 3.96, CI: 1.69-9.28) and seeking treatment from informal sectors (AOR = 0.17, CI: 0.03-0.95). High overall TB knowledge was not statistically associated with seeking health care for TB diagnosis and treatment. We found a substantial delay between the onset of TB symptoms and seeking healthcare from a public health facility providing TB screening services. Promoting early screening and diagnosis through increasing awareness of TB is key in the elimination of TB in communities with a high TB burden.