The current investigation uses the finite element method to analyze the natural convective flow of Casson fluid around a tilted hot rectangular cylinder placed in a square container. The influence of Casson fluid parameter , aspect ratio, () AR , angle of tilt () , and Rayleigh number Ra on isotherms and fluid flow pattern is enunciated. The walls of the enclosure and that of the cylinder are respectively fixed as c T and h T . Results from the findings reveal that for the range of Casson fluid parameter 0.1 1.0 , aspect ratio 0.1 0.7 AR , and Rayleigh number 36 10 10 Ra
, investigated, the rate of heat transfer of the enclosure wall increases with increasing , AR and Ra , while for the heated rectangular obstacle, the rate of heat transfer decreases with AR growth but improves with the growth of and Ra . At 6 10 Ra , improvement in results in heat transfer enhancement for both the enclosure and cylinder walls. However, for Ra in the interval of 35 10 10 Ra , the response of the thermal profiles of both the rectangular cylinder and enclosure walls to cylinder orientation depends on the values of Ra and considered.