| Datasys, s.r.o. | Prague |
| DataVision | |
| DATAWEPS services, s.r.o. | |
| Dateio | |
| David Šauer - DS-SOFT | Prague |
| DCfreenet | Prague |
| DeCe COMPUTERS, s.r.o. | Ústí nad Labem |
| Delnet, s.r.o. | |
| Depo Ventures, s.r.o. | |
| Design CIS s.r.o. | Olomouc |
| Detail.cz | |
| Devart | Prague |
| DEVSENSE, s.r.o. | Prague |
| Dextronet | South Moravian |
| Dexus Internet, s.r.o. | Prague |
| DGIS, spol. s r.o. | |
| Dgstudio.cz, s.r.o. | |
| DHDesign | Prague |
| Dial Telecom, a.s. | Prague |
| Digiskills.cz | |
| Digital Copiers, s.r.o. | Prague |
| Digital Native Agency, s.r.o. | |
| Digital Reality Studios, s.r.o. | Moravian-Silesian |
| Digital Wizards | |
| DigitalVideo, s.r.o. | Prague |
| Digitech ČR, spol. s r.o. | |
| DigiTisk Studio, spol. s r.o. | |
| Digitoo | |
| Digitoo | |
| Dimensio s.r.o. | South Moravian |
| Direct Fidoo, a.s. | |
| DISKUS, spol.s r.o. | Prague |
| Dobrý web, s.r.o. | Prague |
| Dolphin consulting, a.s. | |
| Domena.cz | Prague |
| Doménové centrum | Liberec |
| Domény, s.r.o. | Prague |
| Domotron Holding, s.r.o. | |
| DOPR.cz | South Bohemian |
| Dorset Recruitment | Prague |
| Dosli.cz | Moravian-Silesian |
| Dotidot | |
| Dotu | |
| Dragon Internet a.s. | Central Bohemian |
| Dreamjobs | |
| DS Soft Olomouc, spol. s r.o. | |
| DS Websites | Prague |
| DuCLAIR, s.r.o. | Prague |
| Dunross, s.r.o. | |
| DWC, s.r.o. | Prague |