There is never a wrong time to invest in mutual funds for retirement. So, if you're still looking for the best mutual funds, the Zacks Mutual Fund Rank can be a great guide.

The easiest way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Using the Zacks Mutual Fund Rank of over 19,000 mutual funds, we've identified three outstanding mutual funds that are ideally suited to help long-term investors pursue and achieve their retirement investing goals.

Let's take a look at some of our top-ranked mutual funds with the lowest fees.

Goldman Sachs International Small Cap Insights A (GICAX Quick QuoteGICAX - Free Report) has a 1.22% expense ratio and 0.81% management fee. GICAX is a part of the Non US - Equity fund category, many of which will focus across all cap levels, and will typically allocate their investments between emerging and developed markets. With yearly returns of 10.3% over the last five years, this fund clearly wins.

T. Rowe Price Blue Chip Growth Fund (TRBCX): 0.71% expense ratio and 0.55% management fee. TRBCX is a Large Cap Growth mutual fund, and these funds invest in many large U.S. firms that are projected to grow at a faster rate than their large-cap peers. TRBCX, with annual returns of 11.14% over the last five years, is a well-diversified fund with a long track record of success.

American Funds Washington Mutual Investors R4 (RWMEX): 0.61% expense ratio and 0.22% management fee. RWMEX is a part of the Large Cap Value category, and invests in equities with a market capitalization of $10 billion or more, but whose share prices do not reflect their intrinsic value. With a five-year annual return of 14.88%, this fund is a well-diversified fund with a long track record of success.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.