This doctoral thesis investigates an impact of constructional parameters (ease allowance value and length of clothing garment) on thermal properties of male jackets, expressed as value of effective thermal insulation, as well as satisfaction of the examinees which undergo testing under controlled environmental conditions. Afterwards, an assessment of impact of cool environments and tailor-made clothing garments on satisfaction of examinees was conducted, respectively their influence on thermal comfort was assessed. Subjective perception of thermal comfort while wearing tested clothing in specific environmental conditions was valorised by analysing examinees’ grades, which underwent laboratory trials and completed forms with elaborated subjective judgement scales. Simultaneously, environmental conditions were monitored and physiological reactions of examinees (mean skin temperature and humidity of skin) were measured. The impact of pattern ease allowance on thermal properties of clothing garment were investigated on model of men’s flying wind-proof jacket produced in four variants (each variant differs in amount of ease allowance added to chest and waist circumference). The impact of pattern length on thermal properties of clothing garment was investigated on model of men’s nautical wind-proof jacket produced as modular garment with attachable extensions for pattern length variations. Thermal insulation properties of produced jackets were measured with thermal mannequin and afterwards the examinees, which performed defined physical activities in controlled environmental conditions inside climatic chamber, made subjective evaluation of thermal comfort of clothing garments and ensembles. Two models of male jacket were constructed and made. First model of male jacket is pilot bomber jacket in size 50, but was made in 4 different variants. Each variant was made by adding higher value of ease allowance to chest and waist circumference in garment pattern modification so that the impact of ease allowance value on effective thermal insulation of male jackets can be investigated. Second model of male jacket is modular parka jacket. It consists of one basic module and four applicative modules which can be attached to the basis of the jacket. This model was developed to determine the impact of jacket length on values of effective thermal insulation of clothing garment. Both selected garments and clothing ensembles’’ effective thermal insulation values were determined with thermal mannequin. Basic research problems addressed in this doctoral thesis were: 1) How do constructional parameters affect thermal properties of clothing?, 1a)How much does changes in ease allowance impact the values of effective thermal insulation of male jackets?, 1b) How much does changes in length of jackets impact the values of effective thermal insulation?, 2) Is there correlation between effective thermal insulation of garments and physiological responses of human body?, 3) Is there correlation between effective thermal insulation of ensembles and grades which examinees give while evaluating satisfaction with thermal comfort of clothing?, 4) Does chimney effect or vertical current of hot air occurs in clothing microclimate while the body is moving? Hypothesis appointed upon those questions are: 1) Constructional parameters of clothing affect final thermal properties of clothing garment. 1a) There is connection between the values of ease allowance to chest and waist circumference in garment pattern modification and the final value of effective thermal insulation of male jackets. 1b) There is connection between the values of total jacket length in garment pattern modification and the final value of effective thermal insulation of male jackets. 2) There is correlation between effective thermal insulation of clothing garments and physiological outputs of human body (mean skin temperature and humidity of skin), which are means of evaluating thermal comfort. 3) There is correlation between effective thermal insulation of clothing ensembles and grades of examinees, which are means of evaluating thermal comfort. 4) With body moving, the air with higher temperatures, which is trapped inside microclimatic layer, will start to rise vertically to higher spheres and chimney effect will occur. Than examinees were asked to do laboratory evaluation of selected clothing ensembles, which included those jackets under specific thermal environments. While conducting laboratory testing they were given questionnaire to assess the influence of clothing and environment using subjective judgement scales. Afterwards their answers were compared to values of determined insulation values of clothing ensembles and their physiological responses. Results have shown that by customizing constructional parameters in garment pattern modification, one can affect the final thermal properties of clothing garments and that there is connection between the values of ease allowance to chest and waist circumference and the final value of effective thermal insulation of male jackets. Also it was proven that there is connection between the values of total jacket length and the final value of effective thermal insulation of male jackets. In addition, it was demonstrated that there is correlation between effective thermal insulation of clothing garments and physiological outputs of human body (mean skin temperature and humidity of skin), which are means of evaluating thermal comfort, and that there is correlation between effective thermal insulation of clothing ensembles and grades of examinees, which are means of evaluating thermal comfort. Furthermore, there is evidence that the air with higher temperatures, which is trapped inside microclimatic layer, will start to rise vertically to higher spheres and chimney effect will occur while movements of body.