The current study aimed to estimate the effective doses and conversion coefficients (CCs) for typical barium swallow (BS), barium meal (BM) and barium enema (BE) protocols and to evaluate the impact of different examination parameters on the resulting CCs. Data were collected in surgical and therapy departments in St. Petersburg Urban Mariinsky Hospital. Computational models were developed using PCXMC 2.0 software. CCs (μSv × μGy-1 × m-2) were estimated, as follows, for over couch and under couch exposure geometries, respectively: 2.3 and 1.7 for BS (surgical department); 2.4 and 2.0 for BM (surgical department); 2.6 and 2.1 for BE (surgical department) 2.5 and 3.8 for BM (therapy department). The effective doses and CCs are mainly influenced by the combination of different fluoroscopic series and X-ray images taken in different projections, the irradiation field size and the energy characteristics of the X-ray beam.