Aim: To investigate bioremediation potentiality of Pseudomonas aeruginosa KX828570 on crude oil Polluted Marshland and Terrestrial Soil treated with oil spill dispersant Study Design: The study employs experimental design, statistical analysis of data and interpretation. Place and Duration of the Study: Soil samples were collected from K-Dere, Gokana L.G.A, and were transported to the Microbiology Laboratory of Rivers State University, Port Harcourt, Nigeria for analyses while Oil spill dispersant (OSD/LT and OSD/Seacare) were from Barker and Hughes Nig Ltd (formally mil park Nigeria limited), all in Rivers state, Nigeria. This investigation study lasted for 28 days and sampling was done every 7day period. Methodology: Eight experimental set up were carried out using Pseudomonas aeruginosa KX828570 as the bio-augmenting organism in terrestrial and marshland soil contaminated with two Oil spill dispersant (OSD/LT and OSD/Seacare) separately. Controls for the two soil types were made without organism and treatment. Its bioremediation potential on the pollutants and two types of soil were monitored for 28 days. The setup was tilled twice a week to provide moisture and more oxygen for the organisms to thrive. Analysis of pH, Temperature, Moisture content, Total Hydrocarbon Content, Total Heterotrophic Bacteria, Dispersant Utilizing Bacteria was carried out at weekly intervals. Results: The pH of both soils ranged from 5.75 to 7.37; temperature from 270C to 340C; moisture content 03 to 0.6 across the soil samples. Total Hydrocarbon Content (THC) showed a steady decline from day 1 – 28. The percentage (%) bioremediation rates of polluted soils were as follows: Terrestrial soil+OSD/Seacare+Pseudomonas aeruginosa KX828570 69.4% > Terrestrial soil+OSD/LT+ Pseudomonas aeruginosa KX828570 65.9% > Marshland soil+OSD/Seacare+ Pseudomonas aeruginosa KX828570 52.6% > Marshland soil+OSD/Seacare+ Pseudomonas aeruginosa KX828570 47.6%. Dispersant utilizing bacterial count in marshland and terrestrial soil ranged from 6.013 to 7.338 log10Cfu/g and 6.045 to 7.301 log10Cfu/g respectively from Day 1 to 28. Conclusion:  From the investigation, it revealed that Oil spill dispersants are more degradable in terrestrial soil than marshland soil. OSD/Seacare is more biodegradable than OSD/LT in both terrestrial and marshland soil augmented with Pseudomonas aeruginosa KX828570. Thus, Pseudomonas aeruginosa KX828570 have been found to be a potential bioremediation agent in oil spill dispersant polluted marshland and terrestrial soil.