Background: Excessive and uncontrolled internet use can significantly impair daily functioning in various life domains. Despite the numerous benefits of the internet, its addictive use is a growing concern, particularly among youth, who are prone to anxiety, depression, and stress-related disorders. Understanding the current scenario is essential for devising effective interventions, yet no scientific data is available in Bangladesh. Objective: To assess between depression, anxiety, and stress among youth with problematic internet use (PIU) attending a tertiary care hospital. Methods: This cross-sectional and descriptive study was conducted at the Department of Psychiatry, Department of Bangabandhu Sheikh Mujib Medical University, from October 2020 to September 2022. Participants were interviewed using a structured socio-demographic questionnaire, the Bangla versions of the Internet Addiction Test (IAT), and the Depression Anxiety and Stress Scale-21 (DASS-21-BV). Data were analyzed using SPSS 26.0, with significance set at p<0.05. Results: Among the 90 participants (mean age: 21.33 years; 68% male, 32% female), 95% were students, and 87% were from nuclear families. Internet use exceeded one year for 83% of participants. PIU levels were minimal in 15%, moderate in 62%, and excessive in 22%. Severe depression was observed in 15% of participants, severe anxiety in 25%, and severe stress in 25%. Extremely severe levels of depression, anxiety, and stress were found in 14%, 5%, and 14% of participants, respectively. Significant risk factors for PIU included male gender (χ²=8.217; p=0.02) and over three hours of daily internet use (χ²=35.289; p=0.001). PIU was significantly associated with depression (χ²=20.380; p=0.001), anxiety (χ²=16.159; p=0.019), and stress (χ²=14.734; p=0.019). Conclusion: Depression, anxiety, and stress are significantly associated with PIU. Early risk assessment, proper internet use, and initial screening are essential for managing potential mental disorders linked to PIU.