Projenco's extensive client list includes the following:
- A J Lucas Group Limited
- Abigroup Contractors Pty Ltd
- ATCO Electric (Canada)
- Ateris
- Australian Water Services Pty Ltd
- Barclay Mowlem Construction Limited
- Bardavcol Pty Ltd
- Benchmark Projects Australia
- BGC Contracting Pty Ltd
- BHP Billiton
- BHP Billiton Iron Ore
- Bilfinger Berger Australia
- Black & Veatch Australia Pty Ltd
- Brookfield Multiplex
- Built Environs Pty Ltd
- Burns & Roe Worley Pty Ltd
- Calibre Projects
- City of Belmont
- City of Swan
- CivMec Construction & Engineering Pty Ltd
- Clough Limited
- Connell Wagner
- CSR Emoleum Road Services
- Curtin University, Faculty of Engineering
& Computing
- Defence SA
- Degremont Pty Ltd
- Department for Transport, Energy &
Infrastructure South Australia
- Department of Justice
- DORIC Group
- Downer EDI Ltd
- Electrical Contractors Association
- ERA Pty Ltd
- Ertech Pty Ltd
- Essa
- Fluor Australia Pty Ltd
- Fortescue Metals Group Ltd
- Georgiou Group Pty Ltd
- GHD Pty Ltd
- Gold Coast Water
- GRD Minproc Limited
- Hamersley Iron Pty Ltd
- Iluka Resources Limited
- Infraserv
- Insurance Commission of WA
- John Holland Engineering
- Kelian Gold (Indonesia)
- Kellogg Brown and Root Pty Ltd (KBR)
- Komatsu Australia Pty Ltd
- Koolyanobbing Alliance
- Laing O'Rourke Australia
- LandCorp
- Leighton Contractors Pty Limited
- Lei Shing Hong Machinery (Shanghai)
- Lycopodium Engineering Pty Ltd
- MacCormick Civil & Tunnelling Pty Ltd
- MacMahon Contractors Pty Ltd
- McConnell Dowell Constructors (Aust) Pty Ltd
- Main Roads Western Australia
- Marine & Civil Construction Pty Ltd
- Maunsell/AECOM
- Midland Redevelopment Authority
- Ngarda Civil & Mining
- Parsons Brinckerhoff
- Phelps Dodge
- Pilbara Iron Pty Ltd
- Port Adelaide Maritime Corporation
- Portman Iron Ore Limited
- Project Aurora Alliance
- PT Bayan Resources (Indonesia)
- PT Freeport (Indonesia)
- PT Petrosea (Indonesia)
- PT Trakindo (Indonesia)
- Public Transport Authority
- Rio Tinto Limited
- Robe River Iron Associates
- Roche Mining Pty Ltd
- SA Connexion
- Serck Controls Pty Ltd
- SKM Pty Ltd
- Skyline Constructions
- South East Metropolitan Regional Council
- Southern Gateway Alliance
- SRS Road Services
- Sydney Water Corporation
- Team Savannah
- Tecnicas Reunidas S.A
- Thiess Pty Ltd
- TPI Rail Alliance
- Transfield Services
- United Group Limited
- URS Australia Pty Ltd
- Valoriza Agua
- VDM Group limited
- Veolia Water Australia Pty Ltd
- W.A. Limestone
- Water Corporation of Western Australia
- WorleyParsons