It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.

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.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

If you are looking to diversify your portfolio, consider

Fidelity Balanced Fund K

(FBAKX Quick QuoteFBAKX - Free Report) . FBAKX is classified as an Allocation Balanced fund, which seeks to invest in a balance of asset types, like stocks, bonds, and cash, and including precious metals or commodities is not unusual. This fund is a winner, boasting an expense ratio of 0.4%, management fee of 0.39%, and a five-year annualized return track record of 11.96%.

Janus Henderson Contrarian I

(JCONX Quick QuoteJCONX - Free Report) : 0.62% expense ratio and 0.6% management fee. JCONX is a Large Cap Value fund. These funds invest in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. With yearly returns of 13.45% over the last five years, JCONX is an effectively diversified fund with a long reputation of solidly positive performance.

Putnam Small Cap Growth Y

(PSYGX Quick QuotePSYGX - Free Report) . Expense ratio: 0.96%. Management fee: 0.7%. Five year annual return: 15.27%. PSYGX is a Small Cap Growth mutual fund and tends to feature small companies in up-and-coming industries and markets.

We hope that your investment advisor (if you use one) has you invested in one or all of the top-ranked mutual funds we've reviewed. But if that isn't the case, it might be time to have a conversation or reconsider this vitally important relationship.