| A.T.O.M. | Łódź |
| A3M Sp. z o.o. | Silesian |
| AA Software Solutions | |
| Aasa Polska S.A. | |
| AAT Holding sp. z o.o. | Masovian |
| AB S.A. | Masovian |
| Abacus Internet Solutions Sp. J | Pomeranian |
| ABAStroke | |
| abc.net.pl | Lublin |
| Aberit | Subcarpathian |
| Abris Capital Partners | |
| Abris Design Group | |
| Absysco Sp. z o.o. | |
| Abventor | Lesser Poland |
| AC Software Sp. z o.o. | Masovian |
| Accelpoint | |
| Accelpoint | |
| Accesto | |
| Acclaim Dawid Stasiak | Łódź |
| ACE! Conference | |
| ACEE Europe Sp. z.o.o. | Masovian |
| Acnet Sp. z o.o. | Masovian |
| Acquitec | Lower Silesian |
| ACR Systems | |
| Acrebit Sp. z o.o. | |
| ACSS ID Systems Sp. z o.o. | Greater Poland |
| Active Design | Masovian |
| Active.pl | Łódź |
| ActivePC | Lesser Poland |
| Actualizer | Masovian |
| Adamed | |
| ADASO | Masovian |
| Adchitecs | Greater Poland |
| ADD | Masovian |
| ADD-COM | Subcarpathian |
| Addepto Sp. z o.o. | |
| Adee-Soft Usługi komputerowe | Silesian |
| Adtogame | |
| ADTV Sp. z o.o. | Masovian |
| AdvaCom | Greater Poland |
| Advanced Internet Concepts | Masovian |
| Advanced Protection Systems S.A. | |
| ADVIS | Greater Poland |
| Advy.ai | |
| Aerobits Sp. z o.o. | |
| Aether Biomedical | |
| AF SEKO Sp. z o.o. | Silesian |
| Affbank | Masovian |
| Afterburn | |
| AGBIT Computer Systems | Masovian |