Landmark cases

KSR International v. Teleflex (2007)

Pre-KSR, an obviousness rejection required explicit teaching, suggestion, or motivation in the prior art. Post-KSR, common sense, design needs, and predictable variations all do the work — and most patents don't survive.

5 min read · Updated Apr 29, 2026

KSR International v. Teleflex Inc. is the Supreme Court decision that flexibilized the obviousness test under 35 U.S.C. § 103. KSR freed lower courts and the PTAB from a rigid Federal Circuit framework, making § 103 the workhorse defense it is today.

Decided April 30, 2007, 550 U.S. 398.

Background

Teleflex sued KSR over a patent on an adjustable-pedal assembly that integrated an electronic throttle-position sensor. KSR argued the combination was an obvious union of two well-known elements: adjustable pedals and electronic sensors. The district court agreed and granted summary judgment of invalidity. The Federal Circuit reversed.

The Federal Circuit applied the TSM test (teaching-suggestion-motivation): a § 103 obviousness rejection required that the prior art itself contain explicit teaching, suggestion, or motivation to combine the references. The court found no explicit TSM in Teleflex's prior art and held the patent non-obvious.

KSR appealed.

The holding

The Supreme Court unanimously reversed and articulated a more flexible standard for obviousness analysis:

Throughout this Court's engagement with the question of obviousness, our cases have set forth an expansive and flexible approach inconsistent with the way the Court of Appeals applied its TSM test here.

Key changes:

  • TSM is one path, not the only path. Explicit teaching in the prior art remains a valid rationale for combining references, but courts may also rely on common sense, design needs, market pressure, and the nature of the problem.
  • Common sense matters. A PHOSITA — person having ordinary skill in the art — can have insight beyond what's literally written in the prior art. The Court noted "a court can take account of the inferences and creative steps that a person of ordinary skill in the art would employ."
  • Predictable variations are obvious. When a known technique is applied to a known problem to yield predictable results, the result is obvious.
  • Design incentives. When market forces or design needs create a known motivation to combine, that motivation can supply the obviousness rationale.

The Graham factors survive

KSR didn't displace the older Graham v. John Deere (1966) framework. Courts still:

  1. Determine the scope and content of the prior art.
  2. Identify the differences between the prior art and the claims.
  3. Determine the level of ordinary skill in the field.
  4. Consider secondary considerations (commercial success, long-felt need, failure of others, etc.).

What KSR changed was Step 5 — the legal conclusion of obviousness. Pre-KSR, that step required TSM. Post-KSR, it requires a flexible, holistic analysis.

Aftermath

Obviousness invalidations rose significantly after KSR. The biggest beneficiary was the IPR system, which the America Invents Act launched in 2012 — virtually every IPR petition asserts § 103 grounds, and the PTAB grounds its analyses in KSR almost reflexively.

Patent prosecutors at the USPTO also adapted. Examiners issue § 103 rejections more readily; examining officers cite KSR in their decisions. Average claim scope has narrowed.

The Federal Circuit, after some initial resistance, eventually internalized KSR's flexibility. Today, an explicit TSM is sufficient but not necessary; courts and the PTAB regularly find obviousness on common-sense or design-need rationales alone.

What the patentee can still do

Post-KSR obviousness is flexible but not infinite. Patentees still win § 103 fights with:

  • Hindsight reasoning. A patent that obviously combines known elements only "after the fact" — i.e., the combination wasn't apparent before the patent disclosed it. Courts are more skeptical of this argument post-KSR, but it still wins sometimes.
  • Teaching away. A reference that affirmatively discourages the combination. Real teaching-away can defeat an obviousness combination, but courts apply a high bar — a reference describing "another option" doesn't teach away.
  • Unexpected results. When the combination produces a result that a PHOSITA wouldn't have predicted, that's a powerful indicator of non-obviousness — especially with empirical data.
  • Long-felt need + failure of others. Documented evidence that the field was stuck on a problem and competitors had tried and failed.

Most of these are uphill arguments. The defendant with two solid prior-art references and a clean motivation-to-combine narrative wins more often than not.

What it means for defendants

For a defendant with prior art, KSR is the doctrinal foundation for the obviousness combination. The practical workflow:

  1. Identify the closest single reference (anticipation candidate under § 102 or starting point for § 103).
  2. Identify the missing limitations.
  3. Find a second reference that supplies them.
  4. Articulate motivation to combine using KSR rationales — common sense, design need, predictable variation, or explicit TSM.
  5. Anticipate and rebut the patentee's secondary considerations.

Obviousness under § 103 walks through this in more detail.

Bottom line

KSR is the doctrine that made § 103 the workhorse defense it is today. By rejecting rigid TSM in favor of flexible analysis, the Court empowered lower courts and the PTAB to invalidate combinations that look obvious to anyone with ordinary skill in the field. Most patents that get challenged under § 103 don't survive KSR-grade scrutiny. Pair KSR with Alice for software claims and an obviousness combination becomes hard for any patentee to escape. (See KSR applied to a real patent.)

Read the opinion: KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007).

This article is for general education and is not legal advice.