Objective To determine the effects of cardiac troponin I (cTnI) and brain natriuretic peptide (BNP) on the prognosis of the very old patients with severe pneumonia (SP). Methods A total of 93 very old patients (≥80 years old ) with severe pneumonia admitted to our department from January 2013 to January 2017 were recruited in this study. According to the severity of the disease, they were divided into the SP group (n=40) and ordinary pneumonia group (n=53). The former group was further assigned into death subgroup (n=19) and improvement subgroup (n=21). The plasma cTnI and BNP levels were measured for all the SP patients on days 1,3, 5 and 7 after admission, and in the ordinary pneumonia group on day 1 after admission. SPSS statistics 23.0 was adopted for data processing. Student’s t test or Chi-square test was employed for different data types. Results The plasma levels of cTnI [99.35 (39.95,9.3) vs 7.00 (4.40,1.65) pg/ml] and BNP [566.10 (326.53,5.13) vs 49.10 (24.50,8.30) pg/ml]were significantly higher in SP group than in the ordinary pneumonia group (P<0.05). Compared with the values on day 1, the plasma levels of cTnI and BNP were decreased in the improvement group on days 3,5 and 7 (P<0.05), while those in the death group were increased on days 3,5 and 7 (P<0.05). The levels were obviously lower in the improvement group on days 1,3, 5 and 7 when compared with the death group (P<0.05). Conclusion The plasma levels of cTnI and BNP could be used as adjuvant indicators for assessment of myocardial damage and prognosis in very old patients with SP.