Under the current rules, if a juror becomes unable to serve after the jury retires to deliberate, a mistrial must be declared if one or both parties refuse to stipulate that a verdict delivered by a jury of less than 12 members is valid. The waste of judicial resources that results from a mistrial declared at such a late stage in the proceedings is no longer justifiable because of the recent Supreme Court decision on the right to trial by jury in Henderson v. Lane (1980). The committee's proposed amendment to Rule 23(b) would permit the trial judge to accept a verdict delivered by 11 jurors if the court finds it necessary to excuse a juror for just cause after the jury has retired to deliberate. The proposed amendment to Rule 24(c) would permit the trial court to retain alternate jurors after the jury retires to deliberate. The alternate may be substituted due to juror incapacitation, but deliberations must begin anew. Adoption of the proposed amendment to Rule 23(b), with modifications, is recommended. The article provides 179 footnotes.