Background: Diagnosing pulmonary tuberculosis (TB) in children and non-sputum-producing patients is challenging. Gastric aspirate (GA) provides an alternative for detecting Mycobacterium tuberculosis (MTB). The Cartridge-Based Nucleic Acid Amplification Test (CBNAAT/Xpert MTB/RIF) is recommended as the initial MTB test. This retrospective study evaluated the diagnostic yield and efficacy of Xpert MTB/RIF on GA samples in a tertiary care hospital in New Delhi, comparing it with Ziehl–Neelsen (ZN) staining and Mycobacteria Growth Indicator Tube (MGIT™) rapid liquid culture. Methods: A retrospective analysis of 144 GA samples from 128 patients (aged <1 month to 83 years) with suspected TB between October 2022 and December 2024 was conducted. Samples were tested for MTB and rifampicin resistance using GeneXpert. Results were compared with ZN staining, MGIT culture, and Drug Sensitivity Testing (DST)/First Line Line Probe Assay (FLLPA). Sensitivity, specificity, and diagnostic yield were analyzed. The number of GA samples per patient was 1, 2 & 4. Results: Xpert MTB/RIF showed 100% sensitivity, 94.44% specificity, 55.56% positive predictive value (PPV), and 100% negative predictive value (NPV). Smear microscopy had a lower sensitivity (40%). MTB was confirmed in 6.49% of cultured GA samples. The diagnostic yield was higher in adults (21.43%) than children (4.62%). MTB detection increased with multiple GA samples: 3.51% (1 sample), 11.54% (2 samples), and 50% (4 samples). For rifampicin resistance, Xpert MTB/RIF had 50% sensitivity, 100% specificity, 100% PPV, and 66.67% NPV. Conclusions: Xpert MTB/RIF on GA is effective for early MTB and rifampicin resistance detection in pediatric and non-sputum-producing patients. Multiple GA samples improve diagnostic yield.