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.

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

Emerald Growth Fund Institutional (FGROX Quick QuoteFGROX - Free Report) has a 0.79% expense ratio and 0.62% management fee. FGROX is one of many Small Cap Growth mutual funds; these funds tend to create their portfolios around stocks with market capitalization of less than $2 billion. With yearly returns of 7.16% over the last five years, this fund clearly wins.

Victory Sycamore Established Value R6 (VEVRX Quick QuoteVEVRX - Free Report) . Expense ratio: 0.54%. Management fee: 0.45%. VEVRX is a Mid Cap Value mutual funds that aims to target medium-sized companies that possess strong value and income opportunities for investors. This fund has managed to produce a robust 12.45% over the last five years.

JPMorgan Growth and Income C (VGICX Quick QuoteVGICX - Free Report) : 1.44% expense ratio and 0.4% management fee. VGICX 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. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 10.39% over the last five years.

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.