This is a continued access trial for adult and pediatric patients who have completed treatment with darunavir in combination with low-dose ritonavir (DRV/rtv) in the parent clinical trials TMC114-C211, TMC114-C214, TMC114-TiDP31-C229 or in the parent pediatric trial TMC114-TiDP29-C232 who continue to benefit from the use of DRV/rtv, and who live in a country where DRV is not accessible. At the baseline visit, inclusion and exclusion criteria will be checked to confirm eligibility. Once the eligibility criteria are met, patients will continue treatment as follows: HIV-1-infected patients participating in the TMC114-C211 trial and some HIV-1 infected patients from the pediatric trial TMC114-TiDP29-C232 will continue on the selected DRV/rtv once daily dosing regimen as administered in the original trial, or (for pediatric patients) on an adjusted dose if necessary due to a change in body weight. Some HIV-infected patients from the pediatric trial TMC114-TiDP29-C232 will continue on the selected twice daily DRV/rtv dosing regimen as administered in the original trial, or (for pediatric patients) on an adjusted dose if necessary due to a change in body weight. HIV-1-infected patients having participated in the TMC114-C214 or TMC114-TiDP31-C229 trial will continue on the DRV/rtv 600/100 mg twice daily dosing regimen as administered in the original trial. Visits and assessment are performed according to local standard of care, but desirable every 3 months for pediatric patients and not less frequently than every 6 months for adult patients. The interval between 2 consecutive visits should not exceed 6 months for pediatric patients. Adverse events (AEs) considered at least possibly related to DRV/rtv, AEs leading to discontinuation or treatment interruption, serious AEs (SAEs), and pregnancies (or all AEs if applicable per local regulation) will be recorded at each visit. Patients will be instructed to report any AEs to the investigator, who will report SAEs within 24 hours to the Sponsor. In addition to the assessments in the flowchart, the following assessments are recommended to be performed locally every 3 months or according to local, generally accepted standards of care: efficacy assessments (immunology and plasma viral load) and laboratory safety assessments (hematology and biochemistry, including pancreatic amylase \[if available\] or lipase and lipid analyses). Treatment will be continued until one of the following criteria is met (whichever occurs first): virologic failure; treatment-limiting toxicity; loss to follow-up; withdrawal of consent/assent by the patient; withdrawal of consent by the parent(s)/legal representative(s); pregnancy; termination of the trial by the sponsor; DRV based treatment regimen becomes commercially available for the patients and is reimbursed, or can be accessed through another source (for example, access program, government program) in the region the patient is living in or patients can be switched to local standard of care, as appropriate. A post-treatment follow-up contact is to be performed 4 weeks after the last dose of trial medication for patients with an ongoing adverse event, that discontinue the trial. This is consistent with the primary objective of the study to provide continued access to DRV/rtv for adult patients who previously received DR/rtv in the clinical trials sponsored by Tibotec Pharmaceuticals. This study is not set up to address any specific hypothesis. Depending on the previous trial the patients were in, they will continue to take either : DRV/rtv 800/100 mg once a day as 2 tablets of 400 mg DRV and 100 mg ritonavir; or DRV/rtv 600/100 mg twice a day as 1 tablet of 600 mg DRV and 100 mg ritonavir twice a day; DRV/rtv 375/100 mg twice a day as 1 tablet of 375 mg DRV and 100 mg ritonavir; DRV/rtv selected dose twice daily , or on an adjusted dose if necessary due to a change in body weight. For most of the patients, their next visit will be the final visit with data collection thereafter visits and assessments will be performed per local standard of care and documented in the patient's medical records only. Investigators will continue to report serious adverse events (SAEs) possibly related to DRV/rtv and pregnancies to the sponsor using regular reporting.