Objective: The purpose of this study was to evaluate the role of D-dimer in the diagnosis of suspected pulmonary embolism [PE]. Patients and Methods: This study entailed 40 subjects representing group I; 15 patients clinically suspected as PE and have positive V/Q scan, group II; 15 patients clinically suspected as PE and have negative V/Q scan, and group III; 10 normal volunteers. All participants were subjected to history taking, clinical examination, radiological examination, V/Q scan, and assessment of D-dimer level using an agglutination immunological assay. Results: The sensitivity of D-dimer as a diagnostic marker of pulmonary embolism was 93.3%, specificity 60%, positive predictive value 70%, negative predictive value 90%, and accuracy 76.7%. The sensitivity of D-dimer as a diagnostic marker of pulmonary embolism and/or DVT was 94.4%, specificity 75%, positive predictive value 85%, negative predictive value 90%, and accuracy 86.7%. The results of D-dimer in control group was negative in all subjects. Conclusion: D-dimer had a definite place in the diagnostic procedure for suspected acute pulmonary embolism; when the concentration is below 500μg/L, the diagnosis can be ruled out. D-dimer had a better specificity in the diagnosis of pulmonary embolism when there are no co-morbid conditions as thrombosed piles or recent surgery.