Background: The customary way of diagnosing periodontitis involves evaluating the destruction of periodontal tissue using clinical measurements and radiographic tools. However, saliva has the potential to be a useful diagnostic fluid for oral diseases. The objective of this research was to compare the levels of alkaline phosphatase (ALP) in both saliva and serum, both before and after scaling and root planing, in patients who have chronic generalized periodontitis. Materials and Methods: This study involved a total of 100 participants, of which 50 had chronic generalized periodontitis and 50 were periodontally healthy volunteers. The age range of the participants was between 30 to 50 years. The researchers measured various clinical parameters, including the simplified oral hygiene index (OHI-S), gingival index, probing depth, and clinical attachment loss (CAL). Afterward, samples of saliva and blood were collected from each participant and analyzed for their ALP levels using spectrometry. Following Phase I periodontal therapy, the clinical parameters, saliva, and serum ALP levels were measured again after 30 days. The data were then statistically analyzed using the paired t-test and one-way ANOVA. Results: The study found that subjects with chronic generalized periodontitis had significantly higher levels of ALP in both saliva and serum compared to periodontally healthy individuals. These higher levels of ALP were also associated with increased clinical parameters such as OHI-S, gingival index, probing depth, and CAL. However, after Phase I periodontal therapy, there was a significant decrease in both saliva and serum ALP levels, along with an improvement in clinical parameters. Conclusion: Despite the limitations of this study, it can be concluded that ALP levels in saliva have the potential to be used for the diagnosis of the active phase of periodontal disease, as well as for evaluating treatment outcomes following Phase I periodontal therapy.