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Flow Charts Belong in the Drawings

Written from MPEP 608.02. Examination guidance, not law. Current as of 22 August 2026.

What it says

The written description portion of the specification must not contain drawings or flow diagrams. Tables and mathematical or chemical formulas may appear in the text; illustrations may not. An examiner encountering a flow chart in the description should object and request it be provided as a drawing.

Engineers put a diagram next to the paragraph that explains it. That is correct practice in every document they normally write, and wrong in a patent application.

The manual is explicit: the written description portion of the specification must not contain drawings or flow diagrams. Tables and mathematical or chemical formulas may appear in the text. Illustrations may not.

An examiner who finds a flow chart in the description should object and request that it be provided as a drawing instead.

This is a location rule, not a prohibition on the diagram. The flow chart is welcome. It belongs in the drawings.

Read this alongside what MPEP 2163 says about possession, which records that flow charts are not required for written description. Two different sections, two different questions: one is whether you need the diagram, the other is where it goes if you have one.

What This Does Not Decide

This is not a walkthrough for restructuring an application. Describing where illustrations go is one thing. A step-by-step for reorganising a draft is filing work, and the record for this section draws that line explicitly.
  • It does not tell you how to prepare or restructure an application.
  • It does not say whether any diagram is required. That is a different section.
  • It is not law. The MPEP is examiner guidance.

Educational, not legal advice. Whether any of this reaches a particular application is a determination for a registered patent practitioner.

Sources