Alle Firmen mit dem Anfangsbuchstaben I
- Ing. Osterkorn Tina
- Ing. Ostermann Thomas Robert
- Ing. Oswald Hartlieb
- Ing. Oswald Jenewein Wohnbaugesellschaft m.b.H.
- Ing. Oswald Martin
- Ing. Othmar Möser Bühnen- u. Steuerungstechnik e. U.
- Ing. Othmar Möser Elektroanlagenbau
- Ing. Ott Hilmar
- Ing. Ottmann Walter
- Ing. Otto Berger e.U.
- Ing. Otto DEMEL GmbH
- Ing. P. Weigel KEG
- Ing. Paar Leonhard
- Ing. Pabinger Matthias
- Ing. Pacher Gernot
- Ing. Pacher Siegfried
- Ing. Paczynski Krzysztof Tomasz
- Ing. Paheiner Markus
- Ing. Pahr Noel
- Ing. Palatin Stefan
- Ing. Pall Helmut
- Ing. Palzenberger Markus
- Ing. Pammer Alfred
- Ing. Pamminger-Gruber Julius
- Ing. Pangratz Stefan
- Ing. Pantucek Anton
- Ing. Papalecca Peter Gerhard
- Ing. Papst Motorgeräte
- Ing. Papst Philipp
- Ing. Parik Markus
- Ing. Parschik Markus Roland
- Ing. Parth Michael
- Ing. Parvanov KG
- Ing. Parzer August
- Ing. Parzer Martin Johann
- Ing. Pasching Christoph
- Ing. Paster Daniel
- Ing. Pastl Georg
- Ing. Patrick Feichtner Design & Handel e.U.
- Ing. Patrick J. Pammer - Akkreditierter NIS-Expert
- Ing. Patsch Florian
- Ing. Paul Mario
- Ing. Paulnsteiner Friedrich
- Ing. Pavitsich Berthold
- Ing. Pecksteiner Christian Josef
- Ing. Pein Markus
- Ing. Peischl Robert
- Ing. Peitler Johannes
- Ing. Peking Andreas
- Ing. Pekovsek Michael
- Ing. Pelka Heinrich
- Ing. Pelzmann Christian Matthäus
- Ing. Pelzmann-Pumm Ramona
- Ing. Penn Wolfgang
- Ing. Pensold Andreas
- Ing. Pernegger Stefan Maximilian Alois
- Ing. Persoglia Max
- Ing. Pesendorfer Elektromaschinenbau GmbH
- Ing. Pesenhofer Felix
- Ing. Peter & Sengün GmbH
- Ing. Peter Baumgartner
- Ing. Peter Blecha Holding GmbH
- Ing. Peter Blecha Sachverständigenbüro GmbH
- Ing. Peter Bucher Dachplattenmanufaktur
- Ing. Peter Georg Leitgeb
- Ing. Peter Geusau e.U.
- Ing. Peter Hollaus - techn. Zeichenbüro
- Ing. Peter Holzhammer
- Ing. Peter Kluhs Ges.m.b.H.
- Ing. Peter Knopf
- Ing. Peter Leichtfried
- Ing. Peter Lienbacher-Vrzal e.U.
- Ing. Peter Messner - Technisches Büro - Ingenieurbüro e.U.
- Ing. Peter Rogetzer-Linear Actuator Engineering e.U.
- Ing. Peter Sochor GmbH
- Ing. Peter Tucek GmbH
- Ing. Peter Wiedemann Sachverständigen GmbH
- Ing. Peter Zöhrer GmbH
- Ing. Peterka Stefan
- Ing. Peternel Stefan