Arnold and Kadjan prides itself on its long standing relationships with its clients. The following is a representative list. In most cases, the firm represents the Union as well as its constituent benefit funds.
- Automobile Mechanics Local 701 Welfare and Pension Funds
- Painters District Council No. 14 (Cook, Lake, Will, and Grundy Counties, Illinois)
Painters Welfare, Pension and Apprenticeship Training Funds, along with special assignments from the International Union of Painters and Allied Trades
Since 1980 - Bricklayers Local 74 Pension Fund (DuPage County, Illinois)
Since 1973 - Bricklayers Local 56 Pension Fund(DuPage County, Illinois)
- Cement Masons Local 502(Cook County, Illinois)
Masons 502 Welfare, Pension and Training Funds
Since 1975 - Cement Masons Local 803 (DuPage County, Illinois)
Masons 803 Welfare, Pension and Training Funds
Since 1976 - Indiana District Council of Cement Masons
- Indiana State Council of Plasterers and Cement Masons Welfare and Pension Funds
- International Brotherhood of Electrical Workers Local 701 (DuPage County, Illinois)
IBEW 701 Welfare, Pension and Training Funds
Since 1974 - International Brotherhood of Electrical Workers Local 176 (Will County, Illinois)
IBEW 176 Welfare, Pension and Training Funds
Since 1990 - International Brotherhood of Electrical Workers (Washington, D.C.)
- National Electrical Contractors Association-International Brotherhood of Electrical Workers Family Medical Care Plan
- International Brotherhood of Electrical Workers Local 15
- International Brotherhood of Electrical Workers Local 150 (Lake County, Illinois)
- Carpenters Local 174 (Will County, Illinois)
Carpenters Welfare, Pension and Training Funds - Plumbers Local 422 Welfare, Pension and Training Funds (Central Illinois)
- Plumbers Local 501 Welfare, Pension, and Training Funds
- Glaziers Local 27 (Northern Illinois)
Glaziers Local 27 Welfare, Pension and Training Funds - Suburban Teamsters of Northern Illinois Welfare and Pension Funds
- Teamsters Local 330