<p><strong>Background.</strong> Cardiac surgery in combination with hypothermia, ischaemia and reperfusion leads to an inflammatory response causing postoperative complications. Toll-like receptors are signalling molecules through which some functions of innate immunity can be activated, and polymorphic variants in the TLR-family genes can be predictors of complications after cardiac surgery.<br /><strong>Aim.</strong> To study the associations of TLR-family genes with infectious and non-infectious complications of cardiac surgery for congenital heart defects.<br /><strong>Methods.</strong> The study included 89 children (44 girls and 45 boys) with congenital heart defects who underwent cardiac surgery. Complications occurred in 47 children 47 days after cardiac surgery. There were no complications in 42 children. Genotyping was performed by real-time PCR using TaqMan probes.<br /><strong>Results.</strong> A two-locus model of gene-gene interaction between <em>TLR1</em> rs5743551 and <em>TLR2</em> rs3804099 was the best fit, accounting for 4.01% of phenotypic entropy. The <em>TLR2</em> gene polymorphic variant rs5743708 had the highest predictive potential (2.59%).<br /><strong>Conclusion.</strong> The development of postoperative complications of cardiac surgical treatment for congenital heart defects can be due to the synergistic effect of the polymorphic variants rs5743551 in the <em>TLR1</em> gene and rs3804099 in the <em>TLR2</em> gene. This effect occurs through the features of <em>TLR1</em> and <em>TLR2</em> transcription, the subsequent expression of receptors on cells and signalling which activates the synthesis of proinflammatory cytokines and chemokines.</p><p>Received 25 February 2021. Revised 11 May 2021. Accepted 12 May 2021.</p><p><strong>Funding:</strong> The work is supported by the complex program of fundamental research of the Siberian Branch of the Russian Academy of Sciences (No. 0554-2019-0002).</p><p><strong>Conflict of interest:</strong> The authors declare no conflicts of interests.</p><p><strong>Contribution of the authors</strong><br />Conception and study design: A.V. Shabaldin, A.V. Ponasenko, A.V. Tsepokina<br />Data collection and analysis: A.A. Anikeenko, A.V. Tsepokina, S.A. Shmulevich<br />Statistical analysis: A.V. Shabaldin, A.V. Tsepokina<br />Drafting the article: A.V. Shabaldin, A.V. Tsepokina, A.V. Ponasenko<br />Critical revision of the article: A.V. Tsepokina<br />Final approval of the version to be published: A.V. Tsepokina, A.A. Anikeenko, S.A. Shmulevich, A.V. Ponasenko, A.V. Shabaldin</p>