Tuberculosis is the most distinctive deadly infection causing great mortality amongst all the infectious diseases. The main causative agent of Tuberculosis is Mycobacterium tuberculosis, when resistant to drugs isoniazid and rifampicin together is known as Multidrug Resistant Tuberculosis (MDR-TB). The objective of study was to investigate some haematological parameters (White Blood Cell, Red Blood Cell, Hemoglobin, Hematocrit, Platelets, Erythrocyte Sedimentation Rate) and biochemical parameters (Urea, Creatinine, Uric acid, Sodium, Potassium, Alkaline phosphatase, Alanine transaminase and Bilirubin) in patients who are infected with MDR-TB, conducted in Programmatic Management of Drug resistant Tuberculosis (PMDT) unit at Ayub Teaching Hospital Abbottabad, Pakistan from March 2014 to February 2015. A total of 139 patients and 40 healthy individuals were screened for different investigative parameters. The study comprised of 55.4% female and 44.6 % male subjects. Most of the subjects belonged to rural area (82%), 64 % were married, while literacy rate was 33.1%, belonging to low income families. A significant (P< 0.001) and gradual increase in body weight was been noticed during continuation phase of treatment, which was an indication of recovery from the disease. The level of white blood cells was significantly (P value ranges from 0.001 to 0.05) variable amongst all the age groups. However, a marked decline towards normal level was seen during treatment phase GI5, in age group up to 20 years of male patients. In the age group of upto 20 years the mean hemoglobin level was significantly associated with MDR-TB for both genders at different treatment regimens. However, female had a lower hemoglobin level, but as the treatment was in progression the study experienced a low level of hemoglobin for age group of up to 20 and above 40 years of age in male population. The platelets count was highly varied for female and came to normal in post intensive therapy phase. Erythrocyte sedimentation rate (ESR) was remarkably elevated in all age groups of the respondents during therapy and in intensive phase the ESR flourished towards the normal range. A significant variation (P< 0.001) had been recorded which meant that ESR was highly attributed to MDR-TB patients. Both for urea and creatinine, there was no marked difference noticed, except urea in the male age group of up to 20 years. While in creatinine a prominent alteration was recorded in both the gender of above 40 years of age, which showed that creatinine in the male age group of above 40 years increased during treatment. Observed significant variation in uric acid level for both gender (male and female) up to 20 years of age was (P< 0.05 and 0.01 respectively). While for age group up to 40 years the level of significance varied during the intensive and continuation phase from (P<0.05, 0.01 and 0.001) in both the sexes. The lowest observed sodium level was noted in male age group up to 20 years of age with significant variation (P<0.01). Regarding potassium level in male age group up to 20 years the observed significant variations were (P< 0.05, 0.01 and 0.001) respectively. A prominent significant variation both for male and female of age group up to 40 years were (P< 0.05, 0.01 and 0.001) almost during all treatment phases. Variation (P<0.05) was observed in female of age group above 40 years. Amongst the three age groups the highest significant variation was observed among female up to 40 years of age for alkaline phosphates. Significant variation was found in GO treatment phase for both gender up to age group of 40 years. The lowest sugar value was found 4.62 + 0.78 mmol/L among the male age group of up to 20 years in the treatment, but however it was found that during treatment the level of sugar was found normal. In case of bilirubin no prominent change had been noticed throughout the treatment phase. The liver enzyme Alanine aminotransferase in respect of treatment correspondent to various age groups was found varied in more dramatic way. As the decline of the infection with treatment showed that Alanine aminotransferase level was normalized. It is concluded that MDR-TB treatment produced some serious adverse reactions regarding biochemical abnormalities which resulted in prolongation of treatment and increased hospitalization of MDR-TB patients. Disturbance in liver and kidney functions could play an important role in the pathogenesis of pulmonary tuberculosis. These results showed the importance of the early recognition of these effects and the early initiation of the appropriate approach. Patients who received second line anti-tuberculosis therapy for MDR-TB showed number of side effects. If side effects were not treated, they could had promoted mortality and morbidity.