The present study suggested the use of plant as a model for screening the pathogenic isolates of Pseudomonas aeruginosa from clinical samples in which the pathogenicity level varies from strain to strain. Totally 10 clinical samples were collected, 4 isolates were identified as Pseudomonas aeruginosa. Pathogenicity of the 4 isolates sputum (A), pus (B), urine (C and D) has been evaluated in plant model (Lactuca sativa) by injecting 10 μl of bacteria suspension (0.8 × 109 CFU/ml) into separate smaller (6 cm) and larger (10 cm) lettuce (Lactuca sativa) leaves. The result suggested that isolate (A) seems to be more pathogenic in which the extent of lesion is 86% in large leaf and 97% in small leaf and isolate (B) shows 58% in large leaf and 63% in small leaf which indicates moderate level of pathogenicity. The extent of lesion caused by the isolate C (38% in large leaf and 36% in small leaf) and isolate D (37% in large leaf and 35% in small leaf) indicates low level of pathogenicity. Thus, this study has shown that isolate (A) sputum sample seems to be more pathogenic which has been collected from a patient, suffering from cystic fibrosis. Isolate (B) pus sample indicates moderate level of pathogenicity when compared to other two isolates (C and D) urine samples which indicates low level of pathogenicity. Thus, the pathogenicity among the clinical isolates varies. Thus plants can be used as a model for screening the pathogenic isolates. Further studies should be carried out for those four isolates to check whether it produces the same level of pathogenicity when inoculated in laboratory animals.