Arterial stiffness (AS) is the term used to describe the absence of arterial elasticity. The purpose of this study is to examine the effectiveness of using non-invasive photoplethysmogram (PPG) waveform characteristics to identify changes in arterial stiffness caused by type-2 diabetes mellitus (DM-2). A total of 162 elderly and middle-aged subjects were selected, comprising 80 healthy groups (Group 1) and 82 with DM-2 (Group 2). Demographic (age), hemodynamic (systolic (SBP) and diastolic blood pressure (DBP)), and anthropometric (weight, height, and body mass index) parameters were acquired. A total of eight waveform-based time domain features including second derivative-based features obtained from a 2.1 s PPG signal. The current study’s findings revealed that in terms of the detection of AS the crest time ratio (CTR), and b2/a2 ratio feature (second derivative of PPG-based feature) could segregate those with DM-2 from those without DM-2, as evidenced by statistically significant differences (p < 0.05) in both groups and their significant correlation with age and other demographic parameters. The results could demonstrate its superior sensitivity to subtle arterial stiffness compared to other PPG waveform-related features.