As a commercial laboratory, MCL is responsible for the testing and certification of various types of rubber up to the quality and quantity designated in its agreement with respective customers. Our customers ranged from major rubber producers and surveying companies in Malaysia to overseas rubber trading house. Our current major customers are as follows :
| Customer | Remarks | Since |
| Mardec Processing Sdn. Bhd. – Mentakab, Malaysia | Producer | 1986 |
| Mardec Processing Sdn. Bhd. – Kuala Brang, Malaysia | Producer | 1986 |
| Voon Ming Seng Sdn. Bhd., Malaysia | Producer | 1986 |
| Gan Say Chit (Nam Huat) Sdn Bhd, Malaysia | Producer | 1988 |
| Kuala Pilah Rubber Factory Sdn. Bhd., Malaysia | Producer | 2003 |
| Kian Lee SMR Factory Sdn. Bhd., Malaysia | Producer | 2004 |
| Guangken Rubber Sarawak, Malaysia | Producer | 2012 |
| Southland Tatt Win Rubber Industries Sdn. Bhd., Malaysia | Producer | 2017 |
| Southland Anjahan Sdn. Bhd., Malaysia | Producer/Trader | 2017 |
| Hwah Yang Agro-Industries Sdn. Bhd., Kuching, Malaysia | Producer | 2017 |
| SMPT (Michelin Tyre), Singapore | Buyer | 1989 |
| Pirelli Asia Pte. Ltd., Singapore | Buyer | 1991 |
| Hankook Tire Co., Ltd., Singapore | Buyer | 1999 |
| Kumho Tire Co., Inc., Singapore | Buyer | 2004 |
| The Yokohama Rubber Co., Ltd., Singapore | Buyer | 2005 |
| Continental Tyre Technology Centre Malaysia Sdn. Bhd., Malaysia | Buyer | 2006 |
| Goodyear Orient Company Pte. Ltd., Singapore | Buyer | 2013 |
| Sumitomo Rubber Asia (Tyre) Pte. Ltd., Singapore | Buyer | 2013 |
| Prometeon Tyre Group S.R.L., Italy | Buyer | 2017 |
| Lien Rubber (M) Sdn Bhd, Malaysia | Trader | 1997 |
| Pan Line Consolidated Sdn. Bhd., Malaysia | Trader | 2005 |
| R1 International Malaysia Sdn. Bhd., Malaysia | Trader | 2007 |
| Weber & Schaer GmBH & Co., Germany | Trader | 2005 |
| P.T. Chemicals LLP, England | Trader | 2011 |
| SGS (Malaysia) Sdn Bhd, Malaysia | Surveyor | 1994 |
| CCIC Malaysia Commodities Inspection Sdn Bhd, Malaysia | Surveyor | 2005 |