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Purchase Order Processing

All purchases greater than $10,000.00 (before tax) must be processed using a Purchase Order.

To obtain a PO number, a requisition is entered into Mosaic and approved as necessary. A purchase order is then generated and sent to Strategic Procurement to review before dispatching to the supplier.

Please refer to the Execution of Instruments guidelines for required purchase backup.

For help with processing a purchase order

Email Strategic Procurement:

Processing a PO:

Purchasers at McMaster University may choose to enter their own requisition, or request help from Strategic Procurement (

Review PO requirements here.

If you are entering a requisition, you may need to request access to Mosaic Finance functions.

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Download: How to Enter a Requisition.


The requisition may need to be approved by various people, based on the purchase amount and account being used for the purchase.

The required approvers are outlined in the Execution of Instruments.

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Download: How to Approve a Requisition.

After approval, a Purchase Order is generated.

Strategic Procurement will receive a Purchase Order, and review it. Once processed, the PO will be dispatched to the supplier, and the Requestor will receive notice.

Once a Purchase Order is processed and the goods or services are provided, the PO must be received in order for payment to be issued.

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Download: How to Receive a Purchase Order.

After a Purchase Order has been processed, additional funds can be added by requesting a Change Order. Strategic Procurement will receive your request and add additional lines to your PO.

You may request a Change Order if:

  • your Purchase Order total was under $100,000 (before tax) and will remain under $100,000 with the added funds, or,

  • your Purchase Order total was already greater than $100,000 (before tax) and met the procurement guidelines for purchases of that value, or,

  • you completed a Limited Tender form for the original PO

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Download: How to Submit a Change Order.

If your Purchase Order total was under $100,000 (before tax) and will now exceed $100,000, AND you did not initially complete a Limited Tender approval; you will need to complete a Limited Tender Approval form as well.

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Download: How to Submit a Change Order >$100,000.


Please refer to the Execution of Instruments for Change Order requirements pertaining to Capital Funds.